Snapshot Tinea Capitis A 7-year-old previously healthy boy is brought to the pediatrician with a pruritic scalp and patchy hair loss. His mother reports a close friend at school recently had similar symptoms. Physical exam shows scaly patches with alopecia and black dots. Potassium hydroxide (KOH) preparation shows fungal hyphae around hair follicles. Introduction Clinical definition superficial fungal skin infection of the scalp Epidemiology 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 Pathogenesis dermatophytes live only in keritinized tissues (hair, skin, and nails) symptoms result from host's innate immune response Prognosis excellent since most cases resolve with treatment Presentation Symptoms itchiness 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 used on hairs plucked from affected areas login to view 2 more bullets Wood lamp ultraviolet A (UVA) light login to view 4 more bullets Culture rarely needed can give definitive diagnosis Diagnostic criteria diagnosis typically made by physical exam Differential Alopecia areata autoimmune form of hair loss presents with patchy alopecia with black dots and without scaling Seborrheic dermatitis presents with diffuse scaling on the scalp with erythema and pruritis Psoriasis presents with scaly and 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 1 more bullet medications login to view 6 more bullets Complications May progress to kerion or favus