Phthirus pubis as a cause of axillary pruritus

A 62-year old man with HIV was referred to us for evaluation of underarm pruritus for one month. Previous providers had recommended pramoxine and ketoconazole creams, which did not improve the condition. He reported intimate contact with one male partner. Examination revealed an ill-defined erythematous patch of his left axilla with numerous cream-colored eggs cemented to the base of axillary hairs (Panel A). Microscopic examination of organisms found in the axillary vault revealed live lice; each louse had a short, shield-shaped body, six legs, and was filled with blood (Panel B). The patient was diagnosed with Phthirus pubis infestation (pubic or ‘‘crab’’ lice). Both he and his partner were treated with topical permethrin cream, and asked to shave axillary and pubic hair to remove the nits. He was counseled to launder all clothing and linens. Phthirus pubis classically involves the pubic area, but can also be found in the hairy areas of the scalp, beard, eyebrows and eyelashes. Patients commonly present with pruritus, but eczematization or secondary infection may also occur. A R T I C L E I N F O