Telogen-sparing arthroconidia involvement in an adult case of endothrix tinea capitis

Tinea capitis is a dermatophyte infection of the scalp that most commonly affects children and is relatively rare in adults. In this case, a 66-year-old Italian woman presented with chronic diffuse papulopustular lesions on the scalp. Personal medical history was positive for itching, repeatedly treated with oral antibiotics without improvement. Trichoscopy observed broken hairs, fine desquamation, signs of scalp inflammation, and folliculitis. A punch biopsy of the scalp revealed a moderately dense mixed inflammatory infiltrate with edema and dilated capillaries. Periodic acid-Schiff stain revealed arthroconidia in the hair shaft and in the inner root sheath of the hair follicle. It was additionally noted that arthroconidia were not present in hair follicles in the telogen phase. The fungal culture subsequently showed Trichophyton tonsurans. Therefore, the patient was diagnosed with an endothrix tinea capitis infection and was treated with oral terbinafine, oral corticosteroids, as well as topical ciclopirox and naftifine creams. Considering the relative lack of specific literature regarding the hair cycle involvement of arthroconidia in endothrix tinea capitis infections and the fact that the sources found cited the presence of arthroconidia in both anagen and telogen phase follicles, we present this case of telogen-sparing arthroconidia involvement in an adult with an endothrix tinea capitis infection.