Note the scaly plaque with hair loss in a child.
Note the scaly plaque with hair loss in a child.
Tinea Capitis (TC) is a fungal infection of the scalp. It typically affects young, often black children. In North America, Trichophyton tonsurans has replaced M. canis and M. Audouinii as the predominate dermatophyte. Unfortunately, T. tonsurans is Wood's light negative.
There are several clinical patterns including a seborrheic dermatitis-like pattern consisting mainly of scale, a black dot pattern where the hair is broken off at the base resulting in multiple black dots, and a kerion which is where there is so much inflammation, a boggy, swollen nodule forms. The patient may have acquired the organism through contact with other humans, animal, or fomites (inanimate objects). When a kerion is present, lymphadenopathy as well as a secondary eczema are not uncommon (called dermatophytid). Kerion celsi is an inflammatory form of tinea capitis caused by a T-cell–mediated hypersensitivity reaction to the causative dermatophyte.
The clinical presentation may be highly suggestive. Dermoscopy can be helpful to confirm. Look for comma, corkscrew and zig-zag hairs. KOH analysis is rapid, but does not identify the organism and may not be available in all situations. Scalp lesions should be sampled by scalpel scraping, hair pluck, brush or swab as appropriate. Fungal culture is the gold standard for confirmation of the suspected clinical diagnosis but unfortunately, results may take 3-4 weeks.
With regard to the differential of localized hair loss on the scalp, one should consider alopecia areata, trichotillomania, lupus vulgaris, psoriasis and pseudopelade. The likelihood of tinea capitis is extremely high in a child with alopecia and lymphadenopathy.
In the case of a kerion or a highly suggestive clinical presentation, therapy may be given immediately. Otherwise waiting for culture and identification of the organism is recommended. Terbinafine (2-4 weeks) and griseofulvin (8 weeks) are equally effective for infections by Trichophyton and Microsporum species.
In a nationwide survey, terbinafine was the most common drug prescribed for children 2-18 years of age, griseofulvin for 2 months to 2 years and fluconazole for those 0-2 months of age. In a review, terbinafine was most effective for most cases but griseofulvin may be more effective for M. canis. Oral ketoconazole should NOT be used due to the risk of severe hepatotoxicity.
| Age Range | Commonly Used Drug |
|---|---|
| Newborn - 2 months | Fluconazole |
| 2 months - 2 years | Griseofulvin |
| 2 - 18 years | Itraconazole |
Griseofulvin in FDA-approved for those 2 years and older. Terbinafine is FDA-approved for those 4 years and older. Laboratory monitoring is usually not needed in healthy children. Prolonged treatment, or other health conditions may prompt monitoring in selected cases.
One may also have the patient and any suspected carriers use 2.5% selenium sulfide shampoo OTC 3/week to reduce surface fungal counts. Ketoconazole 2% shampoo is an alternative.
In some cases, an id reaction develops during treatment with an oral antifungal medication. The appearance is that of a fine papular rash and it should be distinguished from a true allergic drug reaction. In the case of an id reaction, the medication may be continued. Also, a secondary eczematous reaction may be present before any treatment is begun, particularly in the case of a kerion.
The black dot pattern where the hair is broken off at the base resulting in multiple black dots.
An inflammatory plaque.
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