Concomitant manifestation of pili annulati and alopecia areata: coincidental rather than true association

The autosomal dominantly inherited hair disorder pili annulati is characterized by alternating light and dark bands of the hair shaft. Concomitant manifestation of pili annulati with alopecia areata has been reported previously on several occasions. However, no systematic evaluation of patients manifesting both diseases has been performed. We studied the simultaneous or sequential occurrence of pili annulati and alopecia areata in individuals diagnosed in different European academic dermatology units. We included 162 Caucasian individuals from 14 extended families, comprising 76 affected and 86 unaffected family members. Statistical analysis showed that the frequency of alopecia areata among patients with pili annulati was higher than within the general population. Five of our patients with pili annulati have gone through severe episodes of alopecia areata. We cannot rule out that the currently unknown genetic defect underlying pili annulati might also confer an increased risk for the development of a more pronounced manifestation of alopecia areata. Based on the current data, and considering the low number within individual families of patients affected by both diseases, however, a direct association between pili annulati and alopecia areata seems unlikely.