Circumscribed scalp hair loss following multiple hair-cutter ant invasion.

A 32-year-old woman presented with an abrupt, localized loss of scalp hair that occurred on the previous day. Her nails, skin, and mucosae were normal. On the vertex of the scalp, there was a circular patch of alopecia; the hairs were broken at approximately equal lengths above the skin surface. Several erythematous macules were seen in the affected area, but scale, twisted hair, and exclamation-mark hairs were not present. Further examination revealed the presence of ants on the scalp. This patient is one of several referred to our department presenting with hair loss associated with hair-cutter ant invasion.