Alopecia as a rare but distinct manifestation of pemphigus vulgaris

Background Pemphigus vulgaris (PV) patients may develop scalp erosions, however, the development of alopecia has been reported to be extremely rare. Objective To delineate the clinicopathological features of alopecia in PV and provide insight into the pathogenesis of this rarely observed manifestation. Methods A retrospective case note review was performed on five PV patients presenting with progressive hair loss and alopecic patches. Data were collected on demographics and clinical findings. Results for hair pull tests, direct immunofluorescence study of plucked hairs, established laboratory tests to detect anti-desmoglein 1 and 3 autoantibodies and scalp swab culture were recorded. A combination of vertical and horizontal sectioning technique enabled detailed histopathological analysis of alopecic patches. Clinical course was monitored. Results Anagen hair follicles with the outer root sheath structure were easily pulled from perilesional scalp, with intercellular IgG deposition on the outer root sheath keratinocytes. Acantholysis between outer root sheath keratinocytes extending from the infundibulum to suprabalbar level was evident in anagen hair follicles of affected lesions. Perifollicular cell infiltration was observed in the lesions where scalp swabs detected micro-organisms. The bulge stem cell area was mostly intact. Alopecia was non-scarring and following 4 weeks of therapy hair re-growth was seen in all patients. Conclusion In PV, the combination of anti-desmoglein autoantibody-mediated acantholysis in conjunction with secondary factors, such as inflammatory changes due to infection, may cause weakening of hair follicle anchorage resulting in hair loss and alopecic patches. This unusual clinical phenotype should alert physicians to PV as a potential diagnosis.