Sleep-related rhythmic movement disorder: A case report of head banging alopecia.

We present a case of alopecia associated with sleep-related rhythmic movement disorder (RMD) in an otherwise healthy 2-year-old boy. The alopecic patch he presented with on his scalp coincided with the location of repeated head banging in a video taken by the patient's mother. Alopecia secondary to RMD is an under recognized entity and should be included in the differential diagnosis of pediatric alopecia.