Uncombable hair syndrome.

A 4-year-old boy was noted to have unruly, spangled hair, which could not be combed flat. His mother reported that his hair had always had that texture and that it seemed to grow slowly. A hair pull test demonstrated that hairs could not be easily extracted, and light microscopic examination of the hair revealed pathognomonic characteristics of uncombable hair syndrome, including a triangular cross-sectional shape and canal-like longitudinal depressions.