Snapshot A 10-year-old previously healthy African-American boy presents to the office with 2 weeks of a pruritic scalp. His mother reports that he has had patchy hair loss, and his two younger brothers have had mild scalp itchiness. She cuts all of their hair with the same hair trimmer. On exam, he has three scaly and circular patches about 3 cm in diameter, as well as alopecia and black dots in the areas of hair loss. He also has diffuse and shotty cervical lymphadenopathy. Introduction Clinical definition superficial fungal skin infection of the scalp Epidemiology Incidence common Demographics most common in pre-pubertal boys more common in African-Americans Location on the scalp ("capitis" = "head") Etiology Infectious agents are fungi called dermatophytes, including Trichophyton Microsporum Acquired through direct contact with the fungus e.g., shared combs and hats athletes with head-to-head contact (wrestling) Presentation Symptoms pruritic scalp with patchy hair loss Physical exam single or multiple scaly patches on the scalp alopecia with small black dots from broken-off hairs cervical lymphadenopathy less common kerion login to view 1 more bullet favus login to view 1 more bullet Studies Labs potassium hydroxide (KOH) prep will show fungal elemants inside or surrounding hair Wood lamp with ultraviolet light if hair fluoresces login to view 1 more bullet if hair does not fluoresce login to view 1 more bullet Culture can be done for definitive diagnosis Diagnostic criteria most commonly diagnosed based on physical findings Differential Alopecia areata autoimmune form of hair loss presents with patchy alopecia with black dots without scaling Seborrheic dermatitis presents with diffuse scaling on the scalp with erythema and pruritis Psoriasis presents with scaly, erythematous plaques that are well-demarcated Treatment Conservative management of close contacts indication login to view 1 more bullet treatments login to view 2 more bullets Medical oral antifungals indication login to view 2 more bullets medications login to view 4 more bullets Complications May progress to kerion or favus Prognosis Excellent since most cases resolve with treatment