Dermoscopy for the Diagnosis of Creeping Hair Caused by Ingrowing Hair: A Case Report.

Creeping hair is a rare condition characterized by creeping eruption with a black line at the advancing end, mimicking cutaneous larva migrans. The condition is also referred to as cutaneous pili migrans, migrating hair, and embedded hair. A total of 52 cases have been reported since 1957 and most cases were published in English. Herein, we report a case in which creeping hair occurred in the iliac region and review the literature from 1957 to February 2021. A 35-year-old Chinese female presented with a black moving linear eruption that had migrated from the lower abdomen to the iliac region without causing any symptoms during a 3-year period. Cutaneous examination showed a 6.5-cm-long black linear lesion beneath the skin that was revealed to be a hair shaft. After removal of the hair, the eruption diminished and no recurrence occurred in 3 months of follow-up. The creeping hair that had migrated with its lower end forward was confirmed by observation under dematoscopy and light microscopy. A review of the literature revealed that creeping hair occurs most frequently in young and middle-aged patients and the reported cases are mainly from Asia. The top locations involve the foot. The causative hair includes head hair, beard, pubic hair, body hair, and one case of dog hair. A close-up examination and dermoscopic inspection are helpful for the diagnosis of creeping hair.