Scalp Hyperkeratosis in Children With Skin of Color: Diagnostic and Therapeutic Considerations
Scalp hyperkeratosis is common in childhood and adolescence. Diagnosis is affected by age, race, and history of infectious exposure, and associated symptoms including atopic features, alopecia, inflammatory nodules, presence and type of cutaneous lesions outside of the scalp, and nuchal lymphadenopathy. Tinea capitis is common in children with skin of color, especially black and Hispanic children. In adolescents, seborrheic dermatitis predominates as the cause of scalp hyperkeratosis, but tinea is still of concern. This article aims to help the practitioner comfortably diagnose and treat scalp hyperkeratosis in children with skin of color.
Practice Points
- Scalp hyperkeratosis is a common finding in children, especially those with skin of color.
- Fungal culture may be helpful in the diagnosis of scalp hyperkeratosis in children of any age but should be performed in patients aged 3 to 11 years with skin of color.
- Therapy of scalp disease in children with skin of color should be adjusted based on hair type and disease features.
Comorbid Skin Disorders
The patient also should be examined for comorbid skin disorders, including tinea corporis, alopecia (particularly in the areas of hyperkeratosis), and the presence of nuchal lymphadenopathy. For each extra clinical finding, the chances of a final diagnosis of tinea capitis rises, allowing for empiric diagnosis to be made that can be confirmed by a variety of tests.1-3
Dermoscopy
Next, the patient should undergo dermoscopic evaluation. On dermoscopy, tinea capitis typically presents with broken hairs, black dots on the scalp, comma-shaped hairs, and short corkscrew hairs, all of which should clear with therapy.30-33 Dermoscopic findings of AD would reveal underlying xerosis and prominent vasculature due to inflammation, and alopecia areata would present with yellow dots at the orifices of the hair follicles, exclamation point hairs, and vellus hairs.34,35 Traction alopecia may be noted by retained hairs along the hairline, which is known as the fringe sign.36
Microscopy and Fungal Staining
Microscopic preparations can be performed to identify tinea capitis using fungal stains of slide-based specimens. Breakage of short hairs onto the slide and/or cotton swab is a soft sign corroborating endothrix infection of the hairs. Potassium hydroxide can enhance visualization of the hyperkeratotic scalp, but for most black patients, use of antifungal agents reduces fungal hyphae and spores in the areas of hyperkeratosis and may limit the utility of examining the skin microscopically. Assessment of the broken hairs obtained by gentle friction with one glass slide and catching the scales onto another glass slide may yield the best results in the evaluation of tinea capitis (a technique taught to me by Robin Hornung, MD, Everett, Washington). Hairs obtained in this manner often are fragile and break due to endothrix infection replacing and weakening the shaft of the hairs. In the United States, fungal samples usually are obtained with cotton swabs, but a recent study suggested that brushing is superior to scraping to obtain samples; the combination of sampling techniques may improve the yield of a culture.37 Because topical agents are unable to enter the hair cortex, the hair shaft is the most likely to show fungal spores under the microscope when antifungal shampoos or pomades are used. Other testing methods such as Swartz-Lamkins or calcofluor white staining can be used on similar scrapings. Biopsy and periodic acid–Schiff staining of thick scales or crust can help differentiate tinea capitis from pityriasis amiantacea when the crust is too thick to be softened via potassium hydroxide preparation.38
Fungal Culture
Fungal culture onto media that contains nutrients for dermatophyte growth can be used for 4 purposes in tinea capitis: (1) to confirm infection, (2) to identify species of infection, (3) to confirm mycological cure when difficulty in clearance of disease has been noted, and (4) to obtain a specimen for sensitivity screening regarding antifungals when necessary, an uncommon but occasionally useful test in individuals with disease that has failed treatment with 1 or more antifungals.27
THERAPY FOR SCALP HYPERKERATOSIS IN CHILDREN WITH SKIN OF COLOR
In patients with scalp hyperkeratosis, it is important to address the specific cause of the disease. Therapy for scalp hyperkeratosis in children with skin of color includes altered hair care practices, use of OTC and prescription agents, and containment of fomites in the case of infections. Biopsy of atypical scalp hyperkeratosis cases is needed to diagnose rare etiologies such as discoid lupus or Langerhans cell histiocytosis. For individuals with systemic disease including Langerhans cell histiocytosis, which is generally accompanied by nodes and plaques in the inguinal region or other intertriginous sites, immediate hematology and oncology workup is required.39 For collagen vascular diseases such as lupus or dermatomyositis, appropriate referral to rheumatology and systemic therapy is warranted.
Altered Hair Care Practices
The use of prophylactic ketoconazole 1% shampoo may not reduce the risk for recurrence of tinea capitis over standard good hygiene, removal of fomites, and adherence to prescribed therapy.40 Use of selenium sulfide has been shown to effectively reduce contagion risk.41
Fragrance- and dye-free shampoos can be helpful in providing gentle cleansing of the scalp, which is especially important in Asian patients who have greater facial and eyelid sensitivity. Free-and-clear shampoos can be used alternatively with shampoos containing selenium sulfide or sulfur to eliminate comorbid seborrhea. Black patients should be advised to shampoo and condition their hair once weekly, and Asian and Hispanic patients should shampoo and condition 2 to 3 times weekly to remove scale and potentially reduce risk for tinea acquisition.42 Children with straight hair should shampoo with increased frequency in the summer to manually remove sweat-induced macerated hyperkeratosis. Conditioners also should be used consistently after shampooing to enhance hair health.
