Woolly Hair Nevus: A Rare Case with Late Onset in Adolescence

The document described a rare case of woolly hair nevus with a late onset at adolescence in a 17-year-old patient, which is atypical as this condition usually begins in early childhood. Woolly hair nevus is marked by a localized area of tightly curled hair on the scalp of a nonblack individual, which may also be lighter in color and associated with skin nevi. Over a period of 5 years, the patient's affected hair became slightly darker and less curly. Microscopic and scanning electron microscopy examinations revealed structural changes in the hair, such as a curved follicle and flattened hair shafts. Despite the clinical improvement, the persistent flattening of the hair shafts suggested that the hair's shape is not solely responsible for its curliness. The document also reviewed the classification of woolly hair and compared this case to previous reports.