Superficial fungal infections can involve the hair, skin, and nails. Most affected children are healthy, although immunosuppression is a risk factor for more severe presentation. Causative organisms typically are members of the Trichophyton, Microsporum, and Epidermophyton genera (dermatophytes), can be acquired from other infected humans, animals, or soil, and illicit a host inflammatory response. Nondermatophyte infections include pityriasis versicolor. In this article, the most common clinical presentations, diagnostic recommendations, and treatment algorithms for dermatophyte and nondermatophyte mycoses in children and adolescents are described.
Key points
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Dermatophyte infections are common in the pediatric population.
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Tinea infections are named by their anatomic location on the body.
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Dermatophyte infections are most often caused by Trichophyton, Microsporum , or Epidermophyton species.
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Most infections can be treated with topical therapy, with important exceptions being the face, scalp, and nails.
Introduction
Superficial fungal infections (mycoses) are caused by specific organisms with the ability to invade and proliferate in keratin-containing layers of the hair, skin, and nails. They are relatively common in the pediatric population. Some organisms induce little host response (such as Malassezia , the causative organism of tinea versicolor), whereas others (the dermatophytes) can lead to marked inflammation (tinea infections). Typical dermatophytes are members of 3 common genera: Trichophyton , Microsporum , and Epidermophyton . The prevalence of certain dermatophytes can vary based on geographic location, whereas others exist worldwide. Infection can be acquired by contact with infected humans (anthrophilic), animals (zoophilic), or soil (geophilic).
Tinea infections are classified by their location on the body ( Table 1 ). Dermatophytoses occur more commonly in children than adults, particularly tinea capitis. Although human immunodeficiency virus infection and immunosuppression can put patients at higher risk and can cause more severe infections, most affected children are healthy without underlying immunodeficiency. Superficial mycoses do not usually penetrate deeper than the superficial layers of skin, hair, and nails, but can lead to significant morbidity because of symptoms, concern for transmission, associated superinfections, and id reactions (discussed later). In this article, the most common manifestations of dermatophyte infections in children are first described, including diagnostic and treatment algorithms and associated phenomena. Clinical presentation and treatment options of superficial skin infections caused by noninflammatory fungal organisms, such as Malassezia , are also described.
| Diagnosis | Location |
|---|---|
| Tinea corporis | Body |
| Tinea pedis | Foot |
| Tinea cruris | Groin |
| Tinea manuum | Hand |
| Tinea faciei | Face |
| Tinea capitis | Scalp |
| Tinea unguium (onychomycosis) | Nail |
Introduction
Superficial fungal infections (mycoses) are caused by specific organisms with the ability to invade and proliferate in keratin-containing layers of the hair, skin, and nails. They are relatively common in the pediatric population. Some organisms induce little host response (such as Malassezia , the causative organism of tinea versicolor), whereas others (the dermatophytes) can lead to marked inflammation (tinea infections). Typical dermatophytes are members of 3 common genera: Trichophyton , Microsporum , and Epidermophyton . The prevalence of certain dermatophytes can vary based on geographic location, whereas others exist worldwide. Infection can be acquired by contact with infected humans (anthrophilic), animals (zoophilic), or soil (geophilic).
Tinea infections are classified by their location on the body ( Table 1 ). Dermatophytoses occur more commonly in children than adults, particularly tinea capitis. Although human immunodeficiency virus infection and immunosuppression can put patients at higher risk and can cause more severe infections, most affected children are healthy without underlying immunodeficiency. Superficial mycoses do not usually penetrate deeper than the superficial layers of skin, hair, and nails, but can lead to significant morbidity because of symptoms, concern for transmission, associated superinfections, and id reactions (discussed later). In this article, the most common manifestations of dermatophyte infections in children are first described, including diagnostic and treatment algorithms and associated phenomena. Clinical presentation and treatment options of superficial skin infections caused by noninflammatory fungal organisms, such as Malassezia , are also described.
| Diagnosis | Location |
|---|---|
| Tinea corporis | Body |
| Tinea pedis | Foot |
| Tinea cruris | Groin |
| Tinea manuum | Hand |
| Tinea faciei | Face |
| Tinea capitis | Scalp |
| Tinea unguium (onychomycosis) | Nail |
Infection of the skin (tinea)
Clinical Features
Tinea corporis
Tinea corporis refers to a dermatophyte infection of the skin on the trunk or extremities, with the exception of the palms or soles. It typically involves exposed areas, but can occur anywhere on the body. Worldwide, the most common causative agents are Trichophyton rubrum and Trichophyton mentagrophytes. Dermatophytes can be acquired from pets, or other animals, usually producing an inflammatory reaction. Close contact during sports, especially wrestling, can also spread organisms. Tinea corporis usually presents as an itchy, erythematous, classically annular plaque of varying size with active peripheral leading scale and central clearing ( Fig. 1 ). Pustules may also be present. The amount of scale can be variable, especially if previously treated by topical corticosteroids, which suppress the host’s local inflammatory response (so-called tinea incognito). Differential diagnosis includes nummular dermatitis and psoriasis, both of which are generally more diffusely distributed and are scaly throughout the lesions. Granuloma annulare can mimic tinea corporis but is characterized by an annular array of dermal, sometimes shiny papules without appreciable scale, often with a dusky or violaceous center, and is usually asymptomatic. A more complete differential diagnosis is presented in Table 2 .
| Tinea Corporis | Tinea Pedis | Tinea Cruris | Tinea Manuum | Tinea Faciei | Tinea Barbae |
|---|---|---|---|---|---|
| Granuloma annulare Cutaneous lupus erythematosus Atopic or nummular dermatitis Pityriasis rosea Psoriasis | Dyshidrotic eczema Contact dermatitis Bacterial or candidal infection Psoriasis Pitted keratolysis | Candidal intertrigo Contact dermatitis Psoriasis | Contact dermatitis Dyshidrotic eczema Atopic dermatitis Psoriasis | Granuloma annulare Cutaneous lupus erythematosus Rosacea Sarcoidosis Seborrheic dermatitis Perioral dermatitis Atopic or nummular dermatitis | Acne Folliculitis Contact dermatitis Herpes zoster Herpes simplex Dental sinus tracts |
Clinical variants of tinea corporis: tinea profunda and Majocchi granuloma
Majocchi granuloma, typically caused by Trichophyton rubrum , is a dermatophyte infection involving the hair follicles on the body. An important clinical clue is the presence of follicular-based pustules or granulomatous nodules ( Fig. 2 ). It commonly occurs on the lower legs, especially in young women who shave, but can occur anywhere that bears hair. It may also be propagated by the use of topical steroids. Tinea profunda is analogous to kerion of the scalp, with a robust inflammatory response to dermatophyte infection, leading to boggy, inflamed cutaneous plaques that can develop secondary abscesses.
Tinea pedis
Tinea pedis, or athlete’s foot, commonly presents in adolescents but is rare in prepubertal children. Occlusive footwear (promoting a warm, moist environment) can predispose patients to the development of fungal infection. Causative organisms also can be shed and transmitted on the floors of locker rooms, swimming pools, and households. There are 4 main clinical presentations: moccasin, interdigital, inflammatory, and ulcerative. The interdigital type is most common and consists of erythema, scaling, and maceration in the web spaces. The ulcerative subtype also has an interdigital distribution, with more severe erosions and ulcers. Diffuse erythema and scaling of the plantar surfaces of the feet characterize the moccasin type ( Fig. 3 ). Inflammatory tinea pedis (often acquired from animals) presents with vesicles, pustules, and blisters on the medial foot. All types can be pruritic, although subclinical disease is also possible. Tinea pedis can also be complicated by bacterial superinfection/impetiginization or cellulitis, and therefore treatment in the immunocompromised population is especially important.
Causative organisms include Trichophyton rubrum, Trichophyton mentagrophytes, and Epidermophyton floccosum. Trichophyton tonsurans is an especially common pathogen in children compared with adults.
Tinea cruris
Tinea cruris, also referred to as jock itch, is a superficial dermatophyte infection of the groin. It can occur in both sexes but is more frequent in males; in the pediatric population, it is most common in teenage boys. It often occurs in conjunction with tinea pedis, because the fungus is autologously spread upwards while putting on pants and undergarments. Other risk factors include both obesity and excessive sweating or participation in athletics, caused by the warm, moist environment this creates. Like tinea pedis, the most common causative organisms include Trichophyton rubrum, Trichophyton mentagrophytes, and Epidermophyton floccosum . Tinea cruris usually presents with erythematous to reddish-brown patches or thin plaques, with scaling and sharply demarcated borders. Pruritus is common. Unlike candidal intertrigo or psoriasis, tinea cruris generally spares the scrotum.
Tinea manuum
Tinea manuum is uncommon in childhood. It usually has a unilateral presentation and may occur in conjunction with tinea pedis in a 1 hand, 2 feet distribution. Onychomycosis/nail involvement of the affected hand may be a clue. It typically presents as mild erythema and diffuse scaling of the palmar surface of the hand, which may or may not be pruritic. Similar to tinea pedis, inflammatory dermatoses (such as dermatitis or psoriasis) may also be considered in the differential diagnosis (see Table 2 ).
Tinea faciei
Tinea faciei is a dermatophyte infection of the face. Its presentation is similar to tinea corporis with erythematous annular plaques with scaly borders, but it can be masked by previous treatment with topical corticosteroids. It commonly begins with small scaly papules that may expand outwards in a ring, and subsequently develop hypopigmentation or hyperpigmentation in the center ( Fig. 4 ). Pustules may also occur. The infrequent nature and variable appearance of tinea faciei make it frequently missed, with as many as 70% of patients being initially misdiagnosed with an inflammatory condition such as dermatitis. Incomplete response or persistence/worsening after treatment with topical steroids should raise suspicion for dermatophyte infection.
