Pili annulati coincident with alopecia areata.

Pili annulati is a rare hair shaft abnormality of unknown pathogenesis which gives a gross beading effect. An association with alopecia areata has been reported. We present a 13-year-old girl who had alopecia areata and coincidentally was found to have pili annulati. Her mother also had pili annulati which had become more noticeable as her hair had become paler with age. We discuss the possible pathogenesis of pili annulati and relate that to the microscopic banding appearance of the hair shaft. We note the relevance of the condition becoming more apparent with age. We also discuss the probable coincidental association with alopecia areata.