A Case of Progressive Evolution of Multiple Woolly Hair Nevi in a Child.

Woolly hair nevus is a rarely acquired disorder of the scalp hair with well-circumscribed patch of curly and unruly hairs which are smaller in diameter than normal surrounding hair. We report a case of progressively evolving multiple woolly hair nevi in a 10-year-old child. Trichoscopy of unruly hairs showed abnormal kinking of hair shafts. Varying diameters of a single hair shaft, damaged cuticle, and trichorrhexis nodosa-like features were observed on hair microscopy. Histopathology showed abnormal bending of hair follicle above the hair bulb and irregularities of inner root sheath near the bulb at the bending. Most of the reported cases of woolly hair nevi had one or two stable patches, but this case presented with four patches which were progressively evolving.