Pediatric Dermatology
Update on Pediatric Psoriasis, Part 1: Clinical Features and Demographics
Pediatric psoriasis consists of infantile psoriasis, a self-limited disease of infancy; psoriasis with onset in childhood; and psoriasis with...
Nanette B. Silverberg, MD
From the Department of Dermatology, Mount Sinai St. Luke’s-Roosevelt and Beth Israel Medical Centers of the Icahn School of Medicine at Mount Sinai, New York, New York.
Dr. Silverberg is an advisory board member for LEO Pharma.
Correspondence: Nanette B. Silverberg, MD, Department of Dermatology, 1090 Amsterdam Ave, Ste 11D, New York, NY 10025 (nsilverb@chpnet.org).
THE BIOLOGY OF HAIR IN CHILDREN WITH SKIN OF COLOR
To some extent, the biology of hair impacts the occurrence, appearance, and treatment of scalp hyperkeratosis in children with skin of color. First, it is important to remember that follicular density is lower in black patients as compared to Asian patients with a consequently lower hair count overall, which results in the easy appearance of hair loss, particularly at the margins of the scalp.19,20 Second, the shape of the hair follicle differs among races and ethnicities. Asian patients have round hair shafts coming from straight follicles, which allows for greater natural hair hydration, resulting in somewhat less aggressive scalp disease. Hispanic patients may have similarly straight hair or may have elliptical or curled shafts, the latter being noted in black patients. Furthermore, a curled hair shaft results in poor flow of sebum across the hair, resulting in greater scalp xerosis, more susceptibility to traction alopecia, and ultimately a greater risk for infections.20-23 Finally, the scalp is continuous with the face and neck, and Asian patients have greater sensitivity to skin care products in these areas, resulting in difficulty of treatment in this patient population and the need for use of gentle products.
HAIR CARE PRACTICES IN CHILDREN WITH SKIN OF COLOR
Hair care in patients with skin of color can be costly, difficult, and potentially damaging, with 99% of black girls reporting pomade or oil usage. Costly and complex hair care practices begin in childhood for patients with skin of color. In a series of 201 surveyed black girls with a mean age of 9.8 years, 80% had used hot combs and 42% used relaxers.24 Traction styles were common with 81% using ponytails, 67% braids, and 49% cornrows in the last 12 months. These styles are thought to affect hair health, particularly through induction of traction-related damage, folliculitis, and alopecia. Furthermore, chemical relaxers, hot combs, blowouts, and hair setting may be introduced during childhood.24 These practices appear to disturb the integrity of the hair follicle, leaving it more susceptible to irritation and infection.
Hair care in the pediatric population often is complicated by the fact that multiple children are being styled in tandem, either at home or in a salon, resulting in shared equipment and fomite spread. Even just proximity to a case of tinea capitis in the household will increase risk for tinea capitis. Furthermore, it is quite commonplace for black patients to use pomades and shampoos that contain antifungals, especially selenium sulfide, which makes it difficult to obtain accurate culture results. In India, use of mustard oil also has been linked to increased risk for tinea capitis.25
Other issues related to hair care include frequent dry scalp in patients with skin of color due to poor sebum distribution along the hair shaft. As a result, frequent washing may exacerbate scalp xerosis and further irritate seborrheic dermatitis and/or AD.
DIAGNOSTIC CONSIDERATIONS FOR SCALP HYPERKERATOSIS IN CHILDHOOD
Dermatologists should have a greater level of suspicion for tinea capitis in black and Hispanic children compared to white children. The index of suspicion should be high given that antifungal shampoos and pomades may minimize the clinical appearance. Although trends in overall incidence in the United States suggest tinea capitis is becoming less common, there still is a stronger representation of the disease in black patients.26 A study of positive fungal cultures from one clinic in Mississippi (N=1220) showed that two-thirds of patients were children younger than 13 years; 87% of patients with positive cultures for dermatophytes were black.27 The endothrix type of tinea capitis caused by T tonsurans often presents with a seborrheic appearance, and fungal culture is warranted in all pediatric patients with skin of color who have scalp hyperkeratosis. Asian children can be regarded with a lower level of suspicion for tinea capitis, similar to white patients in the United States. Variation in incidence of tinea capitis does exist worldwide and the practitioner may need to address these issues in patients who travel or are recent immigrants.
When identifying tinea capitis infections in children with skin of color, physicians should consider the patient’s personal and family history, comorbid skin disorders, dermoscopy, microscopy and fungal staining, and fungal culture (Figure).
A paradigm for the diagnosis of scalp hyperkeratosis in children with skin of color.
Personal and Family History
The first diagnostic consideration is the patient’s personal and family history. A history of AD, asthma, or allergies will support but not confirm the diagnosis of AD. Prior tinea capitis infections and household contacts with tinea infections support the presence of tinea capitis.17 Recent implementation of anti–tumor necrosis factor a inhibitor therapy in a psoriatic child can flare scalp disease, mimicking tinea capitis.28 The patient’s guardians should be queried about potential infectious contacts, whether they themselves have signs of scalp disease or tinea corporis (ringworm) or whether they have a pet with problematic fur. Physicians also should query patients and their guardians about recent use of topical antifungal shampoos, pomades, creams (both over-the-counter [OTC] and prescription), and/or oral antifungals. When these agents are used, there is a possibility that fungal examinations may be negative in the presence of true infection with tinea capitis. Traction alopecia, often preceded by fine scale, is more likely to present in patients who wear their hair in cornrows, while seborrheic dermatitis may be associated with hair extensions, reduced frequency of washing (61% of black girls surveyed wash every 2 weeks), and/or reduced usage of hair oils in black girls.24 Knowledge of the patient’s personal hair care history, such as use of pomades; frequency and method of washing/drying hair; types of hair care products used daily to wash and style hair; use of chemical relaxers; or recent hairstyling with cornrows, braids, or hair extensions, also is essential to the diagnosis of tinea capitis. Usage of traction-related styling practices in patients with chemically relaxed hair can enhance the risk for traction alopecia.29
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