After reading this chapter you should be able to assess, diagnose and manage:
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atopic eczema
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skin infections
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drug eruptions
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urticaria
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skin manifestations of systemic disorders
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ectodermal dysplasia and epidermolysis bullosa
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birth marks, neurocutaneous lesions
Dermatological disorders in children cover an extensive range of clinical problems and presentations. Primary abnormalities of the skin often have a major impact on a child and their family, and some are known to be incompatible with survival. Cutaneous abnormalities are often clearly visible to all, and their impact on the mental health and educational abilities of the individual are often significant and require active and supportive management. Disorders of many other systems may first become evident through their dermatological manifestation, and the ability to recognise and manage these conditions, either directly or through onward referral to a paediatric dermatology service, is part of the skills of the paediatrician.
Atopic eczema
Atopic eczema is a chronic disease with a huge impact on children and families. The aim of treatment is disease control through the avoidance of trigger factors including irritants, the regular use of emollients and the rapid management of flare ups.
Children present with pruritis associated with a chronic fluctuating rash, often on a background of dry skin and the itch may cause sleep disturbance, irritability and distress. The rash often starts on the face in infants ( Figure 23.1 ), but may be anywhere, and often settles in the knee and elbow flexures after 18–24 months of age ( Figure 23.2 ).
The rash is characterised by erythema and itchy papules or vesicles that may become excoriated and lichenified. Eczema may be aggravated by trigger factors including:
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irritants
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ingested or airborne allergens
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infection (systemic or topical)
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intercurrent illness
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stress
Secondary infection with Staphylococcus aureus or Herpes simplex virus is a common complication ( Figure 23.3 ).
Associations
Atopic eczema is frequently associated with other atopic conditions in the child or other family members including asthma, hay fever, allergic rhinitis and food allergy (30% of children with severe eczema have immediate reactions to egg, milk and peanut). Severe eczema which is associated with infections and growth retardation may be a feature of immunodeficiency syndromes ( Table 23.1 ).
| Syndrome | Mode of inheritance | Features |
|---|---|---|
| Hyper-IgE syndrome | (Two variants—AD and AR | eczema, skin abscesses; eosinophilia; elevated serum IgE |
| Netherton syndrome | AR | scaly reddish skin; stunted growth; immunodeficiency; high IgE and low to normal IgG |
| Wiskott-Aldrich syndrome | x linked | eczema; thrombocytopenia; immune deficiency |
Alternative diagnoses and differing features
Seborrheic dermatitis can present as a similar rash in the first few months of life but is generally less itchy and favours the scalp and nappy areas. Psoriasis is more common in older children and presents as a bright red, well demarcated, less itchy rash.
Investigations
Atopic eczema is a clinical diagnosis, but investigations may be helpful in specific circumstances. These include:
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bacterial or viral swabs—to exclude super-added infection
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specific serum IgE and skin prick tests—for exacerbating allergens
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patch tests to look for allergic contact dermatitis
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immune deficiency and growth retardation screen
Treatment and management
Assessment at first consultation should include personal and family history of atopic disease, trigger factors, an examination of the whole skin and an assessment of the impact on quality of life. Atopic eczema is a chronic disease with variable severity, and the aim of treatment is to achieve clearance of lesions and then maintain control through regular application of emollients and rapid treatment of flares by parents. General management measures include:
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avoidance of trigger factors
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use of emollients (for washing and daily application to dry skin)
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education of parents to recognise infection
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education of parents to use active treatment on red, inflamed skin
There is a recognised stepwise approach to the pharmacological treatment of eczema which changes with extent of the disease ( Table 23.2 ).
| mild eczema | moderate eczema | severe eczema | |
|---|---|---|---|
| Emollients | Yes | yes | yes |
| topical corticosteroids | mild potency | moderate potency | high potency |
| steroid example | 1% hydrocortisone | clobetasone butyrate | betamethasone |
| topical calcineurin inhibitors | yes | yes | |
| Bandages | yes | yes | |
| Phototherapy | yes | ||
| systemic therapy | yes |
Relevant pharmacological agents used
There are many different types of emollients, and compliance is better if patients are given a choice. The strength of steroids to be used is determined by the severity of disease, age of child and body sites involved. Side effects of prolonged continuous use include skin thinning, systemic absorption and glaucoma. Potent steroids should not generally be used on the face.
Calcineurin inhibitors, such as topical tacrolimus, are useful if eczema is not controlled by safe maintenance doses of topical steroid or the lesions are present at sensitive body sites such as around the eyes.
Systemic treatment using methotrexate, cyclosporin, azathioprine or mycophenolate mofetil have all shown benefit in severe eczema which is unresponsive to other treatments. The first biological treatment for eczema, dupilumab, has been approved for use in the UK.
Bacterial skin infections
Staphylococcal scalded skin syndrome
This is a blistering disorder affecting neonates and infants and is mediated by epidermolytic toxins produced by Staphylococcus aureus . The toxin leads to intra-epidermal splitting.
Affected infants usually present with prodromal features such as fever and irritability followed by tender erythematous areas in the flexural areas which quickly progress to other areas. Fragile blisters develop which then desquamate leaving a scalded appearance of skin ( Figure 23.4 ). There is no mucosal involvement. Nikolsky’s sign (the sheering of epidermis from dermis upon pressure or the presence of exfoliated epidermis) is typically present. Widespread skin loss in infants can cause temperature instability, fluid and electrolyte imbalance and risk of secondary sepsis.
Investigations
Bacterial swabs from affected sites on the skin may be taken but are often negative as the condition is toxin mediated.
Treatment and management
Prompt initiation of intravenous flucloxacillin is imperative whilst active fluid management is important as fluid loss and electrolyte imbalance do occur in children with extensive desquamation. Staphylococcal scalded skin syndrome resolves usually in 2–4 weeks without any scarring or pigmentation.
Impetigo
Impetigo is the most common acute bacterial skin infection seen in young children. It is contagious and is usually caused by Staphylococcus aureus (rarely Streptococcus pyogenes ) affecting the epidermal layer of skin.
Non-bullous impetigo is the common form and presents with multiple erythematous papules that coalesce, break down, weep and form crusts. The infection can appear at sites of preexisting skin barrier interruption such as atopic eczema, burns, abrasions or chickenpox. Typically, crusts are golden brown, honey coloured over erythematous base and the usual site is the perioral region. Bullous impetigo can affect intact skin and appears as fragile blisters that deroof leaving a raw erythematous base.
Treatment and management
For localised non-bullous impetigo, treatment with topical antibiotics will be adequate but systemic antibiotics are usually required for widespread involvement. If left untreated, toxic shock syndrome and systemic sepsis can occur.
Cellulitis
Cellulitis is infection of deeper tissues (dermis and subcutaneous tissues) usually caused by streptococci and staphylococci and is invariably preceded by trivial trauma to skin. It usually starts with spreading cutaneous erythema, swelling and pain with systemic features such as fever, malaise and lymphadenopathy and often occurs in the extremities and in the periorbital region.
Treatment and management
Oral antimicrobial therapy is adequate for localised cellulitis but intravenous antibiotics are needed if there is spreading cellulitis or the child is systemically unwell. If left untreated then the infection can progress to localised abscess formation, necrotising fasciitis, systemic sepsis and septic shock. Orbital cellulitis may lead to venous thrombosis if not treated adequately.
Scarlet fever
Scarlet fever is an acute bacterial systemic infection caused by toxin-producing strains of Group A streptococcus (GAS), also known as streptococcus pyogenes . It is highly contagious and transmission is by aerosol droplets or direct contact with infective secretions.
Dermatological symptoms and signs include widespread maculopapular rash with sandpaper-like texture, strawberry tongue, flushed cheeks with desquamation of peripheries appearing as the rash settles. Fever and lymphadenopathy are also present. Scarlet fever can easily be confused with glandular fever and Kawasaki disease and it is important to assess and investigate a child to exclude these conditions.
Treatment and management
Treatment with oral penicillin for 10 days will suffice for uncomplicated infections and if the child is penicillin allergic, erythromycin or clarithromycin is preferred.
Potential complications
Suppurative complications with abscess formation at different tissue sites may occur. Nonsuppurative complications are delayed effects and immunologically mediated and include acute rheumatic fever and post-streptococcal glomerulonephritis.
Viral skin infections
Systemic viral infections
Generalised viral exanthems are common among children and although many present with nonspecific signs, some have characteristic systemic features with skin involvement.
Infectious mononucleosis (Epstein-Barr virus, glandular fever) presents a generalised morbilliform rash along with fever, sore throat, exudative tonsillitis, lymphadenopathy and palatal purpura. A lymphocytosis is usually seen.
Measles was uncommon until recently when the uptake of the vaccination fell following misinformation. The child develops a widespread morbilliform rash, Kolpik spots in the buccal mucosa, conjunctivitis and fever.
Roseola infantum (HHV-6 infection) presents with an initial fever and malaise. Its importance for clinical practice is that the initial fever settles after a few days just as the rash appears. It is, therefore, a recognised reason why some individuals are diagnosed with ‘penicillin allergy’ having been started on antibiotics during the febrile period.
Parvovirus produces an erythematous macular rash particularly evident on the face and gives the classical ‘slapped cheek’ appearance. In children with an existing haemolytic disorder such as spherocytosis, an infection with parvovirus can lead to acute haemolysis whilst immunosuppressed children can develop anaemia from bone marrow suppression.
Varicella zoster (chickenpox) is highly contagious and produces a characteristic pleiomorphic rash. The lesions evolve over time and initially appear maculopapular before changing into vesicles and then scabs. All stages will be evident at the same time at the height of the illness.
Localised viral skin infections
Molluscum contagiosum is one of the common localised cutaneous viral infections seen in children, and there is an increased prevalence in children who are immunocompromised or who have atopic eczema. Transmission occurs by close contact or infected fomites. The lesions appear as flesh coloured dome-shaped, pearly, umbilicated papules ( Figure 23.5 ) over face, chest, body, back and legs and genital areas and are generally asymptomatic. Molluscum lesions clear spontaneously over years and therefore treatment is not routinely required.
Viral warts are common in school age children, particularly in children with eczema as a result of skin barrier dysfunction. Transmission occurs by close contact with affected individuals or indirectly through fomites. They can occur anywhere although hands and feet are commonly affected. Common warts are hard, rough hyperkeratotic papules over hands, around nail beds, toes and on the knees whilst plantar warts are rough, flat lesion with tiny black dot in the centre usually seen on plantar surface of the foot. These latter types of warts are often quite painful. Most warts disappear spontaneously without treatment, but if they are painful and limit function then treatment can be offered. Cryotherapy and topical salicylic acid are widely used. Safeguarding issues should be considered in the underlying aetiology if extensive anogenital warts are seen.
Herpes simplex virus infection (HSV-1 and HSV-2) infections are transmitted by direct contact with cold sores or genital herpes. HSV-1 is primarily associated with infections around the mouth, oral cavity and face, and the lesions appear as painful clusters of vesicles that may extend into the gingiva and oral cavity (herpetic gingivostomatitis). HSV-2 lesions predominantly involve the anogenital area.
Children with underlying skin barrier dysfunction such as eczema or burns may develop rapidly disseminating HSV infection known as eczema herpeticum ( Figure 23.6 ). This can be painful and has associated systemic features.
Skin swabs for viral PCR should be sent if the diagnosis is uncertain. Oral antivirals are used to limit the severity of infection and halt progression whilst intravenous antivirals are preferred if the child is systemically unwell.
Fungal skin infections
A number of fungi, moulds and yeast can cause skin infections in children. Most serious fungal infections occur in immunocompromised children where opportunistic infection can lead to systemic fungal sepsis. Common superficial fungal infections include:
Tinea (dermatophyte) infections
Tinea capitis can present as a boggy infected scalp swelling (kerion) and often looks like an abscess. Other features include itchy, circular patches of hair loss with dry, scaling skin, broken-off hair shafts and associated cervical lymphadenopathy. Tinea corporis (ringworm) appears as annular or ring-shaped lesions with central clearing and peripheral fine scales, redness over trunk, arms or legs. Tinea pedis (athlete’s foot) presents as redness, scaling and maceration in interdigital areas whilst Tinea unguium (onychomycosis) affects the nail bed and nail plate leading to brittle nails, fine white powdery surface and thickening of nail plate.
Fungal scrapings from affected sites are important to establish diagnosis and treatment includes oral antifungal agents such as terbinafine and griseofulvin for scalp and nail infections. For tinea corporis and pedis, topical antifungal agents are suitable.
Candida (yeast) infections
These are common in neonates and young infants and are caused by Candida albicans and the common manifestations are oral thrush and napkin dermatitis. Oral thrush typically presents with mucosal involvement with white plaques over tongue, buccal cavity and pharynx that leave a red, raw area underneath when scraped. It can also occur in older children who use recurrent steroid inhalers and recurrent use of antibiotics, as this disturbs oral microbial flora.
Napkin candidiasis describes multiple erythematous, circular ‘satellite-like’ lesions affecting groin areas and buttock region. Napkin candidiasis is one cause of ‘nappy rash.’ Other causes include irritant dermatitis from prolonged contact with urine or faeces, atopic dermatitis, infantile seborrheic dermatitis, napkin psoriasis, allergic contact dermatitis, perianal streptococcal infection, scabies and zinc deficiency (acrodermatitis enteropathica). The diagnosis is usually clinical but skin scrapings help to support the diagnosis and treatment includes topical antifungal agents and oral nystatin.
Infestation
Scabies is an extremely itchy, contagious skin infestation caused by a mite ( Sarcoptes scabeii ) and usually affects more than one member of the family. Transmission is through close contact, sharing bedding and towels and is common in crowded living conditions.
Clinical features
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intense pruritus which is particularly worse at night
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excoriated and scratched areas of skin
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linear burrows in the interdigital spaces ( Figure 23.7 ), wrists, and penis
