Folliculitis decalvans in two families.

Folliculitis decalvans (FD) is a primary cicatricial alopecia characterised by recurrent pustulation, tufting and progressive scarring hair loss. Familial clustering is rarely reported, limiting understanding of potential genetic susceptibility. We describe five cases of FD occurring in two unrelated families: three sisters with adolescent-onset disease and a mother-daughter pair with adult-onset disease, with a possible history in a preceding generation. Clinical and histopathological findings were consistent with FD in all cases. Staphylococcus aureus was identified in three of the affected individuals. Compared with previously reported familial cases, which predominantly involve male relatives or twins, this series represents the largest female-predominant familial cluster and the first clear mother-daughter occurrence. These findings support a potential heritable component in FD and highlight the need for further genomic and mechanistic studies.