The Appearance of Pili Annulati Following Alopecia Areata

Pili annulati is a rare autosomal-dominant hair shaft abnormality. It is characterized by alternating light and dark bands along the shaft due to air-filled cavities within the cortex of the hair shaft. Alopecia areata has been previously described as a common association with pili annulati, with improvement in alopecia areata coinciding with resolution of pili annulati. We report the case of a patient with a history of alopecia areata and alopecia universalis who developed the characteristic banded hair of pili annulati upon resolution of her alopecia areata. We provide direct microscopic examination of postregrowth hairs compared to normal and cross-polarized light microscopy.