Halo Scalp Ring: An Annular Alopecia Associated With Birth Injury

The report described a case of a 24-month-old boy with a halo scalp ring (HSR), an annular alopecia associated with birth injury. The boy had a hairless patch on his left occiput since birth, which partially recovered over time. Histopathological examination revealed miniaturized hair follicles and necrosis of the fat layer, but no perifollicular fibrosis, indicating non-scarring alopecia. The condition was treated with 3% topical minoxidil solution for 10 months, resulting in almost complete recovery. HSR was believed to be caused by ischemic damage due to prolonged pressure on the fetal scalp during delivery. It was considered a benign condition with no systemic involvement, and differential diagnoses included aplasia cutis congenita and alopecia areata.