Long-term pubic dermatitis diagnosed as white piedra.

The case of a 58-year-old man with a pruritic rash involving the pubic area that had been undiagnosed for 30 years is presented. At least 15 different primary care physicians and dermatologists evaluated the patient during this time period. Multiple treatments were unsuccessful and a definitive diagnosis was not rendered. Wood lamp evaluation of the pubic area revealed hair shaft concretions that were confirmed on histologic evaluation to be white piedra (WP). The patient was successfully treated with topical ketoconazole and the eruption completely resolved. Our case raises awareness of the use of Wood lamp and dermoscopy to evaluate for parasitic infections of the pubic hair shafts when nonspecific dermatitis presents in this area.