Dermatologic Disorders

36 Dermatologic Disorders



Peggy Vernon, Margaret A. Brady, Nancy Barber Starr, Ann M. Petersen-smith


The skin is the body’s largest organ and one of its most important. The condition of the skin reflects physical and emotional health, plays a major role in defining identity and supporting survival, and often gives clues to underlying conditions. Skin functions are multiple. Beauty is often defined by the appearance of the skin. Emotions are expressed by blushing and sweating. Skin conveys many impressions through its sensory functions, including reaction to touch, heat, cold, pressure, and pain. Additionally, the skin provides a protective physiologic covering, the first line of defense against injury from chemical, physical, and microorganic invaders. Homeostasis is maintained through fluid regulation and thermoregulation.


Disruptions in the skin account for a significant percentage of all pediatric office visits. The primary care provider plays an essential role in maintaining skin integrity, identifying and minimizing skin disruptions, maximizing healing, and educating parents and children about skin care.


Skin development is constant from embryogenesis throughout life. During the embryonic period (the first 2 months of gestation), the skin differentiates into several layers. The skin changes and develops throughout childhood and adolescence, achieving adult skin thickness and characteristics in the late teenage years. Melanin in the skin reaches adult levels by 1 year of age. Vascularization is well developed by the end of the second year of life. Cutaneous nerves develop until puberty and beyond. Sebaceous glands cease production between 6 and 12 months of age, but become active again at around 7 years old. Eccrine sweat function begins between 2 and 18 days of age, although full function is not in place until 2 or 3 years old. The apocrine glands become active at puberty. Hair grows approximately 1 cm per month. Nails are spoon shaped and thin from infancy until 2 to 3 years old.



image Anatomy and Physiology


The skin is composed of three layers: the epidermis, the dermis, and the subcutaneous layer (Fig. 36-1). Skin, including its epidermis and dermis, varies from 1.5 to 4 mm in thickness (Weston et al, 2007).


image

FIGURE 36-1 Structure of the skin.


(From Jarvis C: Physical examination and assessment, ed 2, Philadelphia, 1996, Saunders.)


The epidermis, the thinner outer layer, functions as a protective barrier between the body and the environment and is comprised of five layers of stratified squamous epithelium. Most epidermal cells are keratinocytes, and the replication and maturation of the keratinocytes is called keratinization. New keratinocytes of the basal layer mature and shed approximately every 28 days. The outer horny layer, the stratum corneum, is responsible for much of the barrier protection against microorganisms and irritating chemicals. It impedes the exchange of fluids and electrolytes with the environment and provides strength for the skin. Melanin protects deoxyribonucleic acid (DNA) from damage by ultraviolet (UV) light irradiation. It is produced in the basal layer of the epidermis and contributes to the color of the skin, eyes, and hair. The water content of the environment influences the epidermal barrier, with either excess or inadequate amounts contributing to microscopic and macroscopic breaks.


The thicker middle layer, the dermis, contributes strength, support, and elasticity to the skin. It is a tough, leathery mechanical barrier that also regulates heat loss, provides host defenses of the skin, and aids in nutrition and other regulatory functions. The dermis is primarily composed of fibrous connective tissue (made up of fibroblasts and collagen), with some elastic fibers and a mucopolysaccharide gel. It includes mast cells, inflammatory cells, blood and lymph vessels, and cutaneous nerves that elicit sensations (touch, pain, pressure, itch, warmth, and cold). These specialized receptors are a defense mechanism to protect the skin surface from environmental trauma.


Underlying the dermis is subcutaneous tissue primarily composed of adipose tissue. It contains arteries and arterioles that assist in skin thermoregulation. The subcutaneous tissue insulates, cushions against trauma, provides energy, and metabolizes hormones.


Skin appendages include the hair, nails, sweat glands, and sebaceous glands. Hair follicles are found over the entire body except for the palms, soles, knuckles, distal and interdigital spaces, lips, glans and prepuce of the penis, and areolae and nipples. Two types of hair can be found on the body. Terminal hair is thick and visible and found on the scalp, axillae, and pubis. Very fine vellus hair is found over the remainder of the body. The visible portion of the hair is the shaft. The hair root is embedded in the dermis as a pilosebaceous unit, consisting of a hair follicle and a sebaceous gland. The hair shaft may be straight, wavy, helical, or spiral. Following an acute febrile illness or stress, there may be hair thinning for several months.


Nails are epidermal cells converted to keratin that grow continually. The nailbed, underneath the nail plate, is composed of layers of epidermis and dermis, which serve as structural support. The nail root lies just under the epidermis.


There are three types of sweat glands. Eccrine glands are distributed over the entire body. They help maintain fluid and electrolyte balance and body temperature, and provide some excretory function. Ceruminous glands are located in the external ear canal and secrete a waxy pigmented substance, cerumen. Apocrine glands are located primarily in the axillary, genital, and periumbilical areas. They open into hair follicles, require androgens to stimulate their secretions, and are thought to be responsible for body odor.


Sebaceous glands, found in conjunction with hair follicles, are distributed over the entire body except the soles, palms, and dorsa of the feet and contribute to the epidermis protection. These glands secrete sebum (oil) when stimulated by androgen and function to prevent excessive water evaporation, minimize heat loss, and lubricate the skin and hair.



image Pathophysiology and Defense Mechanisms


Disruption of the skin and subcutaneous tissue occurs through a variety of assaults. These include:



• Bacterial, fungal, and viral infections


• Allergic and inflammatory reactions


• Infestations


• Vascular reactions


• Papulosquamous and bullous eruptions


• Congenital lesions


• Hair and nail disorders


The skin’s outer layers provide the body’s first line of defense from chemical, physical, and microorganic injury. The epidermis provides a functional barrier, the dermis provides strength and protection through the cutaneous nerves, and the subcutaneous tissue ensures insulation, is a cushion to prevent injury, is an energy source, and functions in hormonal metabolism. These layers, in turn, protect the other body systems. The water content of the skin enhances the protective barrier of the skin. If the skin becomes too dry or too wet, breaks in the barrier elicit an inflammatory response. As a continuously growing system, the skin not only heals itself but controls growth or colonization of microorganisms by continual shedding.


There are three identified cutaneous reactions to trauma, infection, or inflammation: pigment lability, follicular response, and mesenchymal response. Pigment lability occurs as postinflammatory hypopigmentation or hyperpigmentation. If superficial, with changes in the epidermis only, normal pigmentation returns in about 6 months (e.g., in diaper rash, seborrhea, tinea, pityriasis alba). If dermal changes happen, dermal tattooing may occur, causing long-term or permanent changes (e.g., excoriated acne, impetigo, varicella, contact dermatitis). The exaggerated follicular response results in prominent papule and follicle formation, especially with atopic dermatitis, pityriasis rosea (PR), syphilis, or tinea versicolor. The mesenchymal response causes scars and keloids (that extend beyond the edge of the scar), often following varicella, ear piercing, burns, or any surgical procedure.



image Special Dermatologic Considerations in Children With Dark Skin or from Diverse Cultural or Ethnic Groups


Knowledge of the normal variations in children both with different levels of pigmentation of the skin and from diverse ethnic or cultural groups is important for assessing and treating dermatologic conditions. Skin reactions to injury, inflammation, common skin conditions, and cultural practices are varied. A wise pediatric health care provider listens to parents because they are often the first to detect subtle changes in color or texture of the skin. This section discusses some of the dermatologic differences of children with dark skin.


Preventive care for patients with dark skin should be implemented in routine well-child care. The following are initial areas to include:



• Prevent acne or contact dermatitis.


• Avoid pomades.


• Prevent traction alopecia.


• Immunize against varicella to prevent scarring.


• Use insect repellents to minimize insect bite reactions.


• Treat early signs and symptoms of pruritic or inflammatory conditions (acne, eczema) and infections.


• Use moisturizing agents and eliminate soaps for dry, itchy skin.


• Use oral antipruritics for dry, itchy skin.


• Caution about the use of topical medications, especially high-potency steroids, benzoyl peroxide, and isotretinoin.


• Avoid trauma and any procedures that can induce keloids.



Cutaneous Reaction Patterns


Pigment lability is common and tends to be more obvious in dark-skinned individuals regardless of race. People of color are especially prone to the development of keloids and hypertrophic scars, sometimes from relatively minor skin trauma. Other exaggerated responses common in darker-skinned individuals include lichenification and vesicular or bullous reaction to bites or staphylococcal infection. African-American children may have an exaggerated cutaneous response to common disorders of the skin. Of note, erythema of inflamed black skin may be difficult to detect and may appear as a purplish tinge (Paller and Mancini, 2011).



Normal Variations and Common Problems


The following are normal variations or common problems in children with dark skin:



• Variation in color and texture of skin from one part of the body to another


• Pigmentation of gingiva, mucous membrane, sclerae, and nails correlates with degree of cutaneous pigmentation.


• Increased areas of melanin in thicker-skinned areas (elbow, knee)


• The term, Futcher’s or Ito line, describe the vertical line that separates the hyperpigmented dorsal and extensor surfaces from less-pigmented ventral surfaces. This line of differentiation follows Voigt lines and is most noticeable on the extremities.


• Mongolian spots and increased numbers of café au lait spots (see later discussion)


• Normal exfoliation produces a fine layer of gray scales.


• Color alterations (jaundice, anemia, cyanosis) are difficult to assess.


• Kinky, wooly, tightly curled hair with closely knit growth that tangles when dry and mats when wet


• Atopic dermatitis (see Chapter 24) with prominent follicular pattern with pityriasis alba and postinflammatory hypopigmentation



Cultural or Ethnic Practices with Skin Sequelae


Grooming, cosmetic, or healing practices of cultural or ethnic groups contribute to various conditions that may be seen. These include the following:



• Hair pomade—acne


• Bleaching creams—discoloration and erythematous nodules


• Chemical or thermal hair straighteners—alopecia, fragile hair shaft, scalp contact dermatitis


• Tightly braided, twisted, locked hair (dreadlocks), and tight ponytails—traction folliculitis followed by traction alopecia that can be permanent and cause scarring (Putgen, 2008)


• Henna for superficial tattooing—orange discoloration of skin, increased bilirubin levels in infants


• Decorative practices—scars or tattoos


• Healing practices used during significant illness that produce burns—circular 1- to 2-cm scars on chest, periumbilicus, wrists, ankles, or back


• Coining—petechiae and ecchymoses, especially on chest and back


• Cupping—circular ecchymoses on neck, chest, back, and arms



image Assessment of the Skin and Subcutaneous Tissue



History


The history should assess the following:



• History of present illness


image Onset and duration of present or recent illness (e.g., respiratory or gastrointestinal [GI])

image Most common concerns: Pruritus, scaling, and alterations in cosmetic appearance

image Symptom analysis—questions to ask about an eruption or lesions include:

• What did the rash or lesion(s) originally look like?

• How has it changed in appearance?

• Where did the eruption first begin, and has it spread to other locations (pattern of spread)?

• How long has the rash or lesion been present?

• Is the way it looks today typical of its appearance?

• Does the rash come and go?

• Has the lesion blistered, bled, or had discharge?

• Does it itch?

• What have you used to treat it and what was the effect?

image What parts of the body are not affected by the rash or lesions (e.g., face, soles, or palms)?

image Associated systemic symptoms: Fever, malaise, pain associated with lesion or eruption

image Factors that alleviate or worsen skin symptoms or seem to trigger them

image Exposures or allergies: Medication, foods, animals, plants? Known allergens? New substances? Persons with similar symptoms or illness? What soaps, hair products (shampoos, gels, pomade, etc.), lotions, and detergents are used?

image All medication (prescription and over-the-counter) taken over the last few days, including creams, ointments, powders, or lotions (it is often helpful to have patients bring medications they have used to the appointment)

image Prior incidents of similar rash

image Recent travel

• Family review of systems


image Similar symptoms

image Skin disorders or history of atopy disorders (asthma, seasonal or drug allergies or atopic dermatitis)

image Chronic illnesses with related dermatologic findings

• Client review of systems and past medical history


image Usual state of health and recent illnesses

image Skin, hair, and nails: Skin type (dry or oily), recent and long-term changes, previous incidence of skin disease

image Eyes, ears, nose, and throat: Swelling, itching, crusting, discharge or circles around eyes, nasal mucus discharge, patency or irritation, dry mouth, lesions, or pain

image Chest: Wheezing, coughing, or respiratory difficulty

image Chronic illnesses with related dermatologic findings


Physical Examination


When seeing a child with a dermatologic condition, it is essential to assess whether the child is ill. This clinical impression helps the provider differentiate serious illnesses from the majority of dermatologic conditions. The entire body, not just exposed skin, needs to be examined. Attention should be given to the eyes, nose, mouth (mucous membranes, teeth), lymph nodes, and lungs because a skin disorder may be a cutaneous manifestation of other disease. The dermatologic examination includes a thorough look at the skin, scalp, hair, palms and soles, nails, and anogenital region.


Special techniques for examination of the skin may be required. Good light (daylight is best) is essential to a good examination. A source of direct light, such as a gooseneck lamp, is the best alternative. Other helpful tools include a magnifying glass, a ruler, a glass slide, and a Wood’s lamp (UV light). A glass slide gently pressed on the skin (diascopy) allows viewing of the skin with and without capillary filling. A Wood’s lamp is used to examine fluorescent-positive fungal infections and depigmenting skin disorders, such as vitiligo.


Identification of the type of lesion and correct use of terminology are essential to good dermatologic care. Essential documentation includes the following:



• Location and type of lesion


• Color, color changes, size, and shape


• Arrangement (e.g., isolated, grouped, linear, annular, zosteriform)


• Pattern (e.g., sun-exposed area, symmetry)


• Distribution of lesion (e.g., regional, generalized, crops)


• Border (e.g., indistinct, well circumscribed)


• Consistency (e.g., firm, soft, mobile)


Primary skin lesions (Box 36-1) include changes that arise from previously normal skin. These descriptions should be memorized and used. Secondary skin lesions (Box 36-2) result from changes in primary lesions. Vascular skin lesions (Box 36-3) involve the blood supply. Other useful descriptive terms are listed in Box 36-4. Vesicles, pustules, scaling, and color changes should be noted when considering differential diagnoses.



BOX 36-1 Primary Skin Changes to Lesions




Bulla—vesicle larger than 1 cm


Comedo—plugged, dilated pore; open (blackhead), closed (whitehead)


Cyst—palpable lesion with definite borders filled with liquid or semisolid material


Macule—flat, nonpalpable, discolored lesion, 1 cm or smaller


Nodule—raised, firm, movable lesion with indistinct borders and deep palpable portion, 2 cm or smaller


Papule—solid, raised lesion of varied color with distinct borders, 1 cm or smaller


Patch—macule, larger than 1 cm


Plaque—solid, raised, flat-topped lesion with distinct borders, larger than 1 cm


Pustule—raised lesion filled with pus, often in hair follicle or sweat pore


Tumor—large nodule, may be firm or soft


Vesicle—blister filled with clear fluid


Wheal—fleeting, irregularly shaped, elevated, itchy lesion of varied size, pale at center, slightly red at borders



BOX 36-2 Secondary Skin Changes to Lesions




Atrophy—thinning skin, may appear translucent


Crusts—dried exudate or scab of varied color


Desquamation—peeling sheets of scale


Erosion—oozing or moist, depressed area with loss of superficial epidermis


Excoriation—abrasion or removal of epidermis; scratch


Fissure—linear, wedge-shaped cracks extending into dermis


Keloid—healed lesion of hypertrophied connective tissue


Lichenification—thickening of skin with deep visible furrows


Scales—thin, flaking layers of epidermis


Scar—healed lesion of connective tissue


Striae—fine pink or silver lines in areas where skin has been stretched


Ulcer—deeper than erosion; open lesion extending into dermis



BOX 36-3 Vascular Skin Lesions




Angioma or hemangioma—papule made of blood vessels


Ecchymosis—bruise, purple to brown, macular or papular, varied in size


Hematoma—collection of blood from ruptured blood vessel, larger than 1 cm


Petechiae—pinpoint, pink to purple macular lesions that do not blanch, 1 to 3 mm


Purpura—purple macular lesion, larger than 1 cm


Telangiectasia—collection of macular or raised, dilated capillaries



BOX 36-4 Descriptive Terms for Dermatologic Lesions




Acral—involving extremities (hands, feet, ears, etc.)


Annular—ring-shaped


Arcuate—arc-shaped


Circinate—circular


Confluent—running together


Contiguous—touching or adjacent


Diffuse or generalized—scattered, widely distributed


Discrete—distinct and separate


Eczematous—referring to vesicles with oozing crust


Grouped—arranged in sets


Guttate—small, droplike


Herpetiform—referring to grouped vesicles resembling those of herpes


Iris—arranged in concentric circles, one inside the other


Linear—arranged in a line


Localized—in a limited area


Nummular—coin-shaped


Pedunculated—having a stalk


Polycyclic—oval with more than 1 ring


Reticular—netlike


Serpiginous—snakelike, creeping


Symmetric—balanced on both sides


Target lesion—(iris or targetoid) erythematous papule or plaque characterized by a red to violet dusky center surrounded by a raised, edematous pale ring and red periphery


Telangiectatic—referring to dilated terminal vessels


Umbilicated—depressed or shaped like a navel


Verrucous—wartlike


Zosteriform—resembling shingles, following a nerve root or dermatome



Diagnostic Studies


A few simple laboratory tests are helpful in identifying or excluding dermatologic disorders. Proper procurement of the sample is important. Lesions can be scraped with a no. 15 blade or a toothbrush and scales or debris placed on a glass microscope slide or in culture material. The No. 15 blade is also useful for exfoliating a blister. It is important to scrape under any scabs to get a sample of the organisms. Moistening the lesion may facilitate this. Scrapings can be obtained from the edges of skin lesions, from plucked hair (getting the root is essential), from the nail plate, or from subungual debris. Laboratory tests that can be used include the following:



• Microscopic examination of skin scrapings:


image Potassium hydroxide (KOH) can be used to examine for fungal disorders (hyphae or spores; Fig. 36-2). Scrape fine scales from the edge of the lesion onto a glass slide. Add a drop of KOH 20% to dissolve debris, and cover with a coverslip. Let sit for 20 to 30 minutes or heat gently (do not boil). Use × 10 magnification to examine.

image Wright, Giemsa, or Gram stains are used to examine for bacteria or herpes simplex or herpes zoster (HZ) giant cells. Allow scrapings to air-dry, then stain with Wright or Giemsa stain. Use × 40 magnification to examine for bacteria.

• Tzanck smear for herpes, varicella, or zoster


• Microbial culture of lesions for bacteria, viruses, or fungi. Simple, inexpensive culture methods for fungal organisms include the dermatophyte test medium [DTM] and InTray CCD [includes Candida]. Skin or nail scrapings or hairs, including the root, are applied so that they break the agar surface. A color change is noted in 1 to 5 days.


• Patch or skin testing for allergic or contact reactions is usually done by dermatologists or allergists.


• Skin biopsy following local anesthesia may be by punch or shave method for any tumor, palpable purpura, persistent dermatitis, or blister that is not otherwise definitively diagnosed. Such procedures often require referral to a dermatologist.


• Complete blood count (CBC) and erythrocyte sedimentation rate (ESR) may evaluate infection or inflammation.


image

FIGURE 36-2 Fungal elements (hyphae) as seen on microscopic examination of a potassium hydroxide preparation.


(From Hurwitz S: Clinical pediatric dermatology, ed 2, Philadelphia, 1993, Saunders, p 374.)



image Management Strategies



Hydration and Lubrication


Adequate skin hydration is essential to prevent and treat skin conditions. If the skin is overhydrated, the bonds between cells at the stratum corneum loosen and the barrier is broken. If the skin is too dry, it cracks, again breaking the barrier.



Bathing


Bathing is an efficient means of hydrating and lubricating the skin, especially with dry skin or in dry climates. Lukewarm, not hot, water should be used. The bath should last long enough for skin to become moisturized without becoming supersaturated or “pruned.” Bubble-bath solutions are especially irritating and should be avoided. Soaping and shampooing should be done at the end of the bath followed by thorough rinsing. The skin should be gently dried and a lubricating agent applied immediately. See Chapter 24 for further information on lubricating baths. Baths containing baking soda or colloidal oatmeal may help relieve pruritus. Bathing and other heat exposures can make a rash seem worse temporarily.



Environmental Considerations


Because water is essential to skin integrity, environmental humidity also plays a role. Excessive humidity (greater than 90%) or deficient humidity (less than 10%) can cause disruption of the skin. Macerated skin, for example, benefits from less humidity. Itching from excessively dry skin is often relieved by increased humidity provided by using a vaporizer or humidifier. In hot temperatures, itching can be alleviated by air conditioning. Water consumption also plays a role in maintaining proper skin hydration, and children should be encouraged to drink plenty of water.



Skin Care Agents



Soaps, Oils, and Colloids


Mild soaps are best and include Dove, Aveeno, Neutrogena, Basis, Alpha Keri, and Lubriderm. Cetaphil cleanser and Purpose Gentle Cleansing Wash are soap substitutes. Bath oils include Alpha Keri and Domol. Colloids include Aveeno.



Moisturizers and Lubricants


Moisturizers and lubricants treat chronic dryness and inflammation of the skin by retaining water in the skin. Composed of petrolatum or a mixture of petrolatum and lanolin, moisturizers and lubricants are most effective when applied to damp skin. Petrolatum-based lubricants include Moisturel, Purpose, Dermasil cream, Vaseline pure petroleum jelly, and Vaseline Dermatology Formula Lotion. Petrolatum and lanolin combinations include Aquaphor ointment, Eucerin cream and lotion, Lubriderm lotion, and Keri Creme. Glycerin preparations without lanolin or petrolatum include Corn Huskers Lotion, Cetaphil, Keri Light, and Neutrogena.



Sunscreens and Sunblocks


Sunscreens and sunblocks protect the skin from UV light and are graded by their ability to provide sun protection. Daily application of a fragrance-free sunscreen with a minimum sun protection factor (SPF) greater than 30 is recommended (American Academy of Dermatology, 2010). Children who are extremely photosensitive should use sunscreen with levels of SPF 30 or higher. Sunscreens that act by absorbing UV light in the B range include para-aminobenzoic acid (PABA) or PABA esters, cinnamates, salicylates, benzophenones, and anthranilates. Only benzophenones protect from UV rays in the longer UVA range. Sunblocks, including titanium dioxide, zinc oxide, and talc, scatter light and act as protective barriers. They are especially useful on the nose, ears, and lips (see Box 36-10).


Chemical-containing sunscreens should be applied 30 minutes before exposure to the sun to allow binding of the agents to the stratum corneum. Sunblocks can be applied immediately before sun exposure. Reapply sunscreens after swimming, excessive periods of perspiration, or after washing or showering. Sunscreen is never a substitute for sensible sun protection, which includes limiting exposure to intense sun rays. Other protective strategies include wearing protective clothing, hats with visors, and sunglasses with UV protection.



Wet Dressings


For acute oozing, crusting, or itching skin, wet dressings are useful to help dry the skin, decrease itching, and remove crusts. Thin cloths, such as diapers, handkerchiefs, or strips of sheets, make the best wet dressings. Dressings should be moderately wet but not dripping, with lukewarm water and applied for 10 to 20 minutes two to four times daily over a period of 48 to 72 hours. During the treatment dressings must be kept wet either by removing and rewetting or by applying water directly to the dressing. Alternative solutions include saline (1 teaspoon salt with 1 pint of water) or Burow solution (one Domeboro tablet [aluminum acetate; calcium acetate] with one pint of cool or tepid water). The medication in creams or ointments applied following wet dressings is absorbed more effectively. A slightly more intense technique involves applying a steroid ointment or cream to the skin, then covering the skin with a wet dressing and then a dry dressing (e.g., a sleeper, pajamas, or long johns are wetted, put on, and covered with a dry sleeper or long johns) (Weston et al, 2007). The dressing is changed every 6 hours for 24 to 72 hours or is used overnight for 5 to 10 nights. When using this technique, care must be taken to prevent excessive steroidal absorption by applying steroid only to areas needing it, especially in infants and young children.



Occlusive Dressings


Occlusive dressings decrease water evaporation from the skin and enhance hydration and absorption of topical medications. Plastic wrap is placed over the affected area after hydrating the skin and applying cream or ointment; these dressings should not be left on longer than 8 hours. Ointments, oils, urea compounds, and propylene glycol used alone are occlusive. Skinfolds serve as naturally occurring occlusive areas. Lichen simplex chronicus, dyshidrotic eczema, and psoriasis are skin conditions that benefit from occlusion.



Other Considerations




• Irritants and sensitizing agents, such as wool, sweat, and saliva, should be avoided.


• Allergens and foods that most commonly cause skin reactions include milk, eggs, wheat, tomatoes, citrus, chocolate, fish, and nuts.



Medications


Topical treatments are most commonly used for dermatologic conditions. Topical therapy restores hydration, alleviates symptoms, reduces inflammation, protects the skin, reduces scale and debris, cleanses, and eradicates causative organisms.


Thought must be given not only to the medication used in treating skin conditions but also its preparation (Box 36-5) and vehicle (Fig. 36-3), including stabilizers, preservatives, and perfumes. Occasionally an individual is sensitive to a medication vehicle or preparation, and symptoms are aggravated rather than relieved. Common agents that cause sensitization include ethylenediamine, lanolin, parabens, thimerosal, diphenhydramine, propylene glycol, “caines,” and neomycin. The following guidelines for use of preparations may be helpful:



• Acute inflammation—wet dressings, powders, suspension lotions, alcohol- or water-based lotions, or aerosols


• Chronic inflammation—creams, oil-based lotions or gels, ointments


• Patient’s tolerance for and willingness to use certain vehicles


• Patient’s environment (dry or humid)



BOX 36-5 Preparations of Topical Medications




Creams—contain more water than oil and therefore are less occlusive; better used with less dry skin, in high-humidity areas, in summertime, and on parts of body that naturally cause occlusion (body folds); often accepted better by patient, but must be applied every 2 to 3 hours


Gels—alcohol based, provide good penetration of skin, but can burn on application; primarily used for acne and in hairy areas


Lotions—mixtures of powder and water, useful for drying, cooling, and soothing actions; emulsion lotions contain some oil, so are not as drying as lotions; lotions come in suspension or solution


Oils—fluid fats that hold medication to the skin as barriers or occlusive agents


Ointments—best used with dry skin; composed primarily of oil with little or no water; provide most potent concentration of medication because of their occlusive action on skin; generally need to be used only every 12 hours; tend to leave a greasy feeling and can cause heat retention from decreased evaporation


Pastes—made of a combination of powder and oil, which makes them somewhat difficult to apply and remove, but effective in providing dryness and protection for skin


Powders—absorb moisture and reduce friction, provide cooling, decrease itching, increase evaporation


Shampoos—liquid soaps or detergents for cleaning the hair and skin (e.g., tar for psoriasis or seborrhea, antifungal shampoos for tinea versicolor or tinea corporis)


image

FIGURE 36-3 Vehicles for dermatologic therapy. See Box 36-5 for description.


All topical medications except powders have enhanced absorption if applied to skin immediately after it has been saturated with water. Occlusion enhances absorption (skinfolds or plastic wraps; see previous discussion). Application of the topical medication is best done in one direction, preferably along the hair follicles, without rubbing, applied with a single motion. Use an adequate but not excessive amount.



Antibacterial Agents


Topical antiseptics, soap, and antibacterial soap reduce the number of bacteria on the skin and provide thorough cleansing. Examples of antiseptics include povidone-iodine, chlorhexidine gluconate, and pHisoderm. Topical antibiotics, such as bacitracin, polymyxin B, mupirocin, or retapamulin applied directly to the skin, are used to treat minor skin infections. Products containing neomycin should be avoided because of the high incidence of contact sensitization. Oral antibiotics used to treat more significant bacterial infections include penicillins, erythromycin, cephalosporins, and tetracycline. If methicillin-resistant Staphylococcus aureus (MRSA) is suspected, obtain a culture and sensitivity of the drainage (see Chapter 23).



Antifungal Agents


Many topical antifungals are over-the-counter medications. Oral antifungals are used for hair and nail infections or refractory skin infections. Because of concerning side effects and minimal clinical experience in children, oral antifungals should be used with caution in children; many of these drugs are not U.S. Food and Drug Administration (FDA) approved for pediatric use (antifungal agents are listed in Table 36-4).



Antiviral Agents


Topical antivirals are used to control cutaneous herpes infections. Oral antivirals, such as acyclovir, can shorten the course of the infection and should be used in children with acute or recurrent herpetic skin infections.


Wart therapy agents destroy keratinocytes. These include salicylic acid and lactic acid collodion, salicylic plaster, salicylic solution, liquid nitrogen, cantharidin, podophyllum, and trichloroacetic acid.



Antiacne Agents


Topical keratolytics are used in acne to relieve follicular obstruction by inhibiting bacteria and promoting peeling of the skin. The two most common keratolytics are benzoyl peroxide and retinoic acid. They are the first line of treatment for mild acne and are used in combination with other agents for moderate or severe acne. Topical antibiotics have few side effects and are most effective in maintaining control of acne. Clindamycin, erythromycin, and sulfacetamide are the most commonly used topical antibiotics. Systemic antibiotics such as tetracycline, doxycycline, minocycline, and erythromycin, are effective in treating inflammatory acne. Antibiotics work by decreasing the population of Propionibacterium acnes. The oral retinoid, isotretinoin, is effective in nodulocystic acne that is not responsive to other combination treatments. Patients taking isotretinoin should be monitored by a dermatologist, with tightly controlled follow-up and prescriptions. The use of isotretinoin is contraindicated in pregnancy because of teratogenic effects. Some estrogen containing oral contraceptives are being combined with antiandrogen for treating acne. Studies have shown ethinyl estradiol-drospirenone and ethinyl estradiol-cyproterone to be most effective (Thielitz and Gollnick, 2009). Photodynamic therapy is also an option.



Antiinflammatory Agents


Topical glucocorticoids are frequently used to reduce inflammation, decrease itching, and promote vasoconstriction without causing the widespread systemic effects of oral steroids. They are subdivided into three categories: high potency, moderate potency, and low potency (Table 36-1). It is important to note that steroids are classified as fluorinated or nonfluorinated. Nonfluorinated steroids are less potent and have fewer side effects.



TABLE 36 -1 Topical Corticosteroids

image

Primary care providers should rarely use high-potency topical steroid preparations. Only low-potency steroids should be used on the face, buttocks, groin, and axillae. Always use the lowest potency available, use them sparingly, and for the shortest length of time. The key to using topical steroids is to be familiar with a few low-, medium-, and high-potency steroids and use them consistently. Brand-name preparations often have a more consistent base and potency. Ointments are more potent than creams, creams are more potent than lotions, and foams are better in hairy areas. Absorption is enhanced in areas that are traumatized or denuded. Potential side effects of prolonged topical steroid use include skin atrophy, striae, increased fragility of the skin, hypopigmentation, secondary infection, acneiform eruption, folliculitis, miliaria, hypertrichosis, telangiectasia, and purpura.


Oral glucocorticoids (prednisone) are used only in acute situations and are limited to short courses. Intralesional steroid injections may be used by a dermatologist to control localized eczema, lichen planus, or psoriasis.



Antipruritic Agents


Antihistamines are used both for sedation and to relieve itching. The most commonly used antihistamines are hydroxyzine, cetirizine, fexofenadine, and diphenhydramine. Topical antihistamines, especially diphenhydramine HCl and “caine” medications, should be avoided because of the possibility of contact sensitization. Menthol and pramoxine are topical anesthetics that do not cause sensitization (Patel et al, 2007).



Topical Calcineurin Inhibitors


This class of immunosuppressive, nonsteroidal antiinflammatory topical medication is used for short-term or intermittent long-term treatment of atopic dermatitis when conventional therapy is inadvisable, ineffective, or not tolerated. Immunomodulators are expensive and cannot be used in children younger than 2 years of age (see Chapter 24).



Scabicides and Pediculicides


These agents are toxic to mites and lice. Crotamiton (Eurax), permethrin (Elimite, Nix), and pyrethrin plus piperonyl butoxide are used in children but should be used sparingly. Lindane (Kwell) is no longer recommended for use in children.



Hair and Scalp Preparations


Antimicrobial, tar, keratolytic, and detergent shampoos are used on the hair and scalp.



Counseling and Anticipatory Guidance


It is essential to spend adequate time with the patient and parents to discuss the child’s skin condition and the family’s concerns and needs. Education regarding the disease, plan of treatment, and potential risks and benefits should be provided. Because disorders of the skin are so visible, time must be spent discussing the short- and long-term prognoses and potential plans to prevent complications, recurrence, and spread.



image Bacterial Infections of the Skin and Subcutaneous Tissue


Diagnosis and treatment of common bacterial infections are listed in Table 36-2.



TABLE 36 -2 Diagnosis and Treatment of Common Bacterial Infections

image


Impetigo



Description


Impetigo is a common contagious bacterial infection of the superficial layers of the skin. It has two forms: nonbullous, with honey-colored crusts on the lesions, and bullous (see Color Plate).



Epidemiology


Impetigo is usually caused by group A streptococcus, Staphylococcus aureus, or MRSA. Often streptococcus and staphyloccus can be cultured from an impetigo lesion. Nonbullous impetigo accounts for more than 70% of cases, with S. aureus as the most common pathogen rather than group A streptococcus as had occurred in the past, and usually follows some type of skin trauma (e.g., bites, abrasions, varicella) or another skin disease such as atopic dermatitis. Bullous impetigo occurs sporadically, develops on intact skin, and is more common in infants and young children. Certain epidermal types of S. aureus produce a toxin that causes bullous skin lesions.


Bacterial colonization of the skin occurs several days to months before lesions appear; the organism usually spreads from autoinoculation via hands, towels, clothing, nasal discharge, or droplets. Impetigo occurs more frequently with poor hygiene; during the summer months; in warm, humid climates; and in lower socioeconomic groups. Streptococci that cause pharyngitis rarely cause impetigo and vice versa. Secondary bacterial infections of underlying skin problems (dermatitis, varicella, psoriasis) are most commonly caused by staphylococci (Weston et al, 2007).



Clinical Findings



History




• Pruritus, spread of the lesion to surrounding skin, and earlier skin disruption at the site


• Weakness, fever, diarrhea may accompany bullous impetigo



Physical Examination


The following can be found:



• Nonbullous, classic, or common impetigo—begins as 1- to 2-mm erythematous papules or pustules that progress to vesicles or bullae, which rupture, leaving moist, honey-colored, crusty lesions on mildly erythematous, eroded skin; less than 2 cm in size; little pain but rapid spread


• Bullous impetigo—large, flaccid, thin-wall, superficial, annular, or oval pustular blisters or bullae that rupture, leaving thin varnish-like coating or scale


• Lesions are most common on face, hands, neck, extremities, or perineum; satellite lesions near the primary site, although they can be found anywhere on the body


• Regional lymphadenopathy



Diagnostic Studies


Gram stain and culture are ordered if identification of the organism is needed in recalcitrant or severe cases.



Differential Diagnosis


Herpes simplex, varicella, nummular eczema, contact dermatitis, tinea, kerion, and scabies are included in the differential diagnosis.



Management


Management involves the following:



• Topical antibiotics may be used if the impetigo is superficial, nonbullous, or localized to a limited area. Topical treatment alone provides clinical improvement, but may prolong the carrier state (Weston et al, 2007). Mupirocin and retapamulin are the best choices for topical treatment (Koning et al, 2008; Weinberg and Tyring, 2010; Weston et al, 2007; Yang and Kearn, 2008). Polymyxin B, gentamicin, and bacitracin are less effective (Parish and Parish, 2008).


• Oral antibiotics are recommended for multiple lesions or nonbullous impetigo with infection in multiple family members, childcare groups, or athletes. Treat for S. aureus and Streptococcus pyogenes because coexistence is common (Cole and Gazewood, 2007; Weston et al, 2007).


image Amoxicillin/clavulanate: 90 mg/kg/day for 10 days

image Cephalexin: 40 mg/kg/day for 10 days

image Dicloxacillin: 15 to 50 mg/kg/day for 10 days

image Cloxacillin: 50 to 100 mg/kg/day for 10 days

image Clindamycin: 10 to 25 mg/kg/day for 10 days

• For widespread infection with constitutional symptoms and deeper skin involvement, use an oral antibiotic active against beta-lactamase–producing strains of S. aureus, such as amoxicillin/clavulanate, dicloxacillin, cloxacillin, or cephalexin.


• If an infant has bullous impetigo, use parenteral beta-lactamase–resistant antistaphylococcal penicillin, such as methicillin, oxacillin, or nafcillin.


• If there is no response in 7 days, swab beneath the crust and do Gram stain, culture, and sensitivities. Community-acquired MRSA should be considered. This organism is more susceptible to clindamycin and trimethoprim-sulfamethoxazole (TMP-SMX) (see Chapter 23 for treatment of MRSA).


• Educate regarding cleanliness, handwashing, and spread of disease.


• Exclude from daycare or school until treated for 24 hours.


• Schedule a follow-up appointment in 48 to 72 hours if not improved.



Complications




• Cellulitis may occur with nonbullous impetigo and present in the form of ecthyma (infection involving entire epidermis) or erysipelas (spreading cellulitis with induration).


• Lymphangitis, suppurative lymphadenitis, guttate psoriasis, erythema multiforme (EM), scarlet fever, or glomerulonephritis may occur following infection with some strains of Streptococcus. Acute rheumatic fever is a rare complication of streptococcal skin infections.


• Staphylococcal scalded skin syndrome (SSSS) is a blistering disease that results from circulating epidermolytic toxin–producing S. aureus. SSSS is most common in neonates (Ritter disease), infants, and young children less than 5 years of age. It manifests abruptly with fever, malaise, and tender erythroderma, especially in the neck folds and axillae, rapidly becoming crusty around the eyes, nose, and mouth. Nikolsky sign (peeling of skin with a light rub to reveal a moist red surface) is a key finding. Treatment may include hospitalization and parenteral antibiotics, especially for young children (Berk and Bayliss, 2010). Antibiotics of choice are intravenous (IV) or oral dicloxacillin, a penicillinase-resistant penicillin, first- or second-generation cephalosporins, or clindamycin. Quicker healing without scarring results if steroids are avoided, there is minimal handling of the skin, and ointments and topical mupirocin are used at the infection site (Aronson and Florin, 2009; Berk and Bayliss, 2010). Severe cases may need treatment similar to extensive burn care.



Patient Education and Prevention




• Thorough cleansing of any breaks in the skin helps prevent impetigo.


• Postinflammatory pigment changes can last weeks to months.


• The patient should not return to school or day care until 24 hours of antibiotic treatment is completed.



Cellulitis



Description


Cellulitis is a localized bacterial infection often involving the dermis and subcutaneous layers of the skin. It is commonly seen following a disruption of the skin surface from an insect or animal bite, trauma, or a penetrating wound. Cellulitis is more common in children with diabetes and immunosuppression. Periorbital cellulitis is discussed in Chapter 28.



Epidemiology


In children cellulitis is often periorbital, perivaginal, perianal, or buccal, or it involves a joint or an extremity. Streptococcus pneumoniae and S. aureus are the most common causes (Fisher et al, 2009; Morelli, 2007). Buccal cellulitis and infections over joints are most commonly caused by Haemophilus influenzae and occur in 3-month-olds to 3-year-olds (Weston et al, 2007). Periorbital and orbital cellulitis are most commonly caused by streptococcal species (S. pneumoniae and group A beta-hemolytic streptococcus [GABHS]). Most cases of cellulitis of the extremities and perianal area are caused by streptococci or S. aureus (Fisher et al, 2009). MRSA can also cause cellulitis with pus accumulation. Rarely, other aerobic, anaerobic, and fungal organisms can cause cellulitis in immunocompromised individuals.



Clinical Findings



History




• A previous skin disruption at the site or recent upper respiratory infection (H. influenzae). Note that edema that occurs within 24 hours of an insect bite is most likely to be inflammatory, whereas edema that occurs between 48 to 72 hours is more likely to be infectious.


• Fever, pain, malaise, irritability, anorexia, vomiting, and chills can be reported.


• Recent sore throat or upper respiratory infection


• Anal pruritus, stool retention, constipation, and blood-streaked stools



Physical Examination




• Erythematous, indurated, tender, swollen, warm areas of skin with poorly demarcated borders


• Blue to purple tinge to the cellulitis is often associated with H. influenzae (Weston et al, 2007)


• Regional lymphadenopathy


• Well-demarcated perianal erythema up to 2 cm around the anus. The erythema may extend to the vulva and vagina (Gerber, 2007).


• Erysipelas—a superficial variant of cellulitis—presents with rapidly advancing lesions that are tender, bright red, have sharp margins and an “orange peel” look and feel.



Diagnostic Studies


CBC and blood culture are done if the child is febrile, appears ill or toxic, or is less than 1 year of age. Leukocytosis is common. Blood cultures are positive in less than 5% of cases (Fisher et al, 2009). Perform gram stain and culture of the erythematous area if unusual organisms are suspected, pus is present (which is more typical of MRSA), or the child looks toxic. An aspirate at the point of maximum inflammation is more likely to yield a causative organism than one taken from the leading edge, though the bacterial counts tend to be low with either method (Morelli, 2007; Weston et al, 2007). Gram stains and cultures lead to identification of the causative organism in less than 25% of cases (Fisher et al, 2009).



Differential Diagnosis


Pressure erythema, giant urticaria, contact dermatitis, Popsicle panniculitis, early erythema nodosum, subcutaneous fat necrosis, herpetic whitlow, and diaper dermatitis are included in the differential diagnosis.



Management


Immediate antibiotic therapy is needed.



• Hospitalization is recommended if the child is a febrile neonate or infant, is acutely ill or toxic, or has periorbital cellulitis.


• Neonates with cellulitis require a full septic workup and initiation of empiric therapy with methicillin or vancomycin and gentamicin or cefotaxime (Morelli, 2007).


• Antibiotic therapy


image Prompt administration of antibiotics is essential.

image If a streptococcal infection is suspected, penicillin is the drug of choice.

• A hospitalized febrile acutely ill infant or child should have penicillin up to 2 million units per day.

• Benzathine penicillin: 600,000 to 1,200,000 units IM for one dose

• Penicillin V: 30 to 60 mg/kg/day orally for 10 days

• If allergic or concern for multiple organisms a third-generation cephalosporin, such as 50 to 75 mg/kg ceftriaxone intramuscularly (IM) once a day

image If suspected organism is staphylococcus:

• An initial IM dose of ceftriaxone 50 to 75 mg/kg/dose, then dicloxacillin 50 to 75 mg/kg/day orally, divided four times a day for 10 days or cephalexin 50 to 100 mg/kg/day orally, divided three times a day for 10 days

• If MRSA suspected, clindamycin 10 to 30 mg/kg/day orally divided three times a day for 10 days

image If suspected organism is H. influenzae:

• Amoxicillin clavulanate 50 to 80 mg/kg/day orally for 10 days

• Methicillin or a third-generation cephalosporin is also an option.

• Follow up in 24 hours to assess response and observe toxicity. Continue daily visits until child is recovering. Counsel parents to call the provider immediately or return for an urgent visit if the infection is not improving or getting worse.


Complications


Recurrent perianal streptococcal infection, septicemia, necrotizing fasciitis (NF), and toxic shock syndrome (TSS) are possible complications.



• NF is a rare infection in children and has two subtypes. Type I is generally a polymicrobial infection that usually affects children who have an underlying disease. Type II, commonly referred to as flesh-eating strep, is an acute, rapidly progressing necrotic invasion of GABHS through the skin and subcutaneous tissue to the fascial compartments. It is more common in otherwise healthy children or children with varicella. NF is more common in boys less than 5 years of age and children with diabetes, skin injury, surgery, immunodeficiency, IV drug use, malnutrition, and obesity (Leung et al, 2008; Weston et al, 2007). NF begins as cellulitis (usually on the leg or abdomen in infants) with severe pain, edema, fever, and bullae on an erythematous surface. It quickly progresses to ulcer, eschar, and gangrene within 2 days. Prompt treatment (hospitalization, surgical debridement, and fluid management), prolonged antibiotic treatment (penicillin), and IV immunoglobulin (IVIG) may be lifesaving because the overall mortality rate is high.


• TSS is an acute febrile illness with rapid onset that causes significant fever, vomiting and diarrhea, engorged mucous membranes, hypotension, a diffuse macular or sunburn-like rash, conjunctival injection, and multiple organ system involvement. S. aureus or S. pyogenes (group A streptococci) are the causative agents associated with TSS, and incubation can be as little as 14 hours. Both organisms can be associated with invasive infection (e.g., pneumonia, osteomyelitis, bacteremia, or endocarditis) or focal tissue invasion that is rapidly progressive (American Academy of Pediatrics [AAP], 2009). Initially recognized in menstruating adolescents, TSS is also found in males and younger children. S. aureus is usually the causative agent in menstruating females. Nasal packing, surgical procedures, and postpartum condition are some factors linked to nonmenstrual TSS. Treatment is intensive, requires hospitalization, and consists of fluid management, antibiotics, and other supportive measures. Staphylococcal TSS has a mortality rate of 3%, whereas streptococcal TSS has a mortality rate of 30% to 60% (Berk and Bayliss, 2010). It is a reportable disease in most states.



Prevention




• Thorough cleansing of any break in the skin helps prevent cellulitis.


• Keep bites, scrapes, and rashes clean and bandaged until healed to prevent them from being infected by staphylococcal bacteria.


• Frequent handwashing is essential; immunize against H. influenzae.


• Perianal spread can occur through shared bath water.


• See Chapter 23 regarding treatment of children and families with MRSA infection.

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Jul 24, 2016 | Posted by in PEDIATRICS | Comments Off on Dermatologic Disorders

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