This 2-year-old girl developed a 3 cm scaly bald spot on her occiput associated with pruritus and scale. There was a bright red border that was suppressed with the application of a moderate potency topical steroid. A potassium hydroxide preparation showed long strands of hyphae and spores on the exterior of the fractured hair shafts typical of ectorhtix infection. Further questioning revealed that the family recently acquired a kitten from a local animal shelter and that her older sister was treated for 3 patches of tinea corporis the preceding week. A culture was sent for confirmation of the diagnosis. The most common organism cultured in this setting is Microsporum canis which is usually acquired from pet kittens. Oral antifungal agents are required to treat tinea in hair bearing areas such as the scalp.
3 cm round scaly plaque with broken hairs and multiple 1-2 mm blue-green fluorescent papules on Wood light examination