240 - Tinea capitis

Abstract

Tinea capitis is a fungal infection of the scalp caused by dermatophyte species, most commonly Microsporum and Trichophyton, which are identified on microscopy and culture. Infections localized to the inside of the hair shaft, known as endothrix infections, are most commonly caused by Trichophyton species. Ectothrix infections, which affect both the inside and the outside of the hair shaft, are most commonly caused by Microsporum species. Tinea capitis typically presents as patchy alopecia with varying degrees of erythema and scale with associated lymphadenopathy. A ‘black dot’ appearance, caused by breakage of hair shafts, indicates an infection with an endothrix species such as Trichophyton. Scrapings and samples of loose, fractured hairs should be processed for microscopy and culture. Swabs may provide an accurate, non-invasive alternative. Wood lamp examination may also aid diagnosis and trichoscopy is a useful, non-invasive diagnostic adjunct. Treatment of tinea capitis is with oral antifungal agents as topical therapy alone is insufficient. Topical antifungal creams and shampoos may help when used in conjunction with systemic treatment in reducing infectivity by reducing fungal elements and the shedding of spores but should not be used alone or as prophylaxis. The aim is to eradicate the organism to prevent further transmission to others and scarring. Where possible, one should await confirmation of a fungal infection. The response of different dermatophyte species to different systemic agents is variable and treatment should be tailored accordingly. General consensus is that griseofulvin is more effective for the treatment of Microsporum infections and terbinafine against Trichophyton. While griseofulvin is an established therapeutic, evidence suggests that newer systemic antifungals (terbinafine and itraconazole) are equally safe and may be more cost effective.