Background: Frontal fibrosing alopecia (FFA) is a primary lymphocytic scarring alopecia occurring mainly in postmenopausal women. A range of facial lesions have been described in FFA, such as lichen planus (LP) pigmentosus, red dots, facial papules, and perifollicular and diffuse erythema. These lesions can be the first sign of FFA. LP pigmentosus is a rare variant of LP. The first description of LP pigmentosus associated with FFA (in 2012) reported 22 cases of LP pigmentosus among 44 cases of FFA affecting South African patients.
Methods: We reviewed 16 FFA patients with LP pigmentosus and the histopathological findings of the biopsy of LP pigmentosus in 9 patients.
Results: Most patients had intermediate skin phototypes (III-IV; n = 10; 62%). The age at onset of LP pigmentosus ranged from 30 to 60 years. The most common histopathological findings were epidermal atrophy, basal cell degeneration, interfollicular inflammatory infiltrate and melanophages, and perifollicular changes. Other findings not previously described in LP pigmentosus were inflammation and interface changes on sweat duct epithelia (acrosyringium and superior dermal duct), and lichenoid perisebaceitis.
Conclusions: Histology of our cases confirmed previous findings and showed a high incidence of perifollicular involvement with occasional changes affecting sebaceous and sweat glands.
Keywords: Alopecia; Cutaneous lichen planus; Frontal fibrosing alopecia; Histopathological findings; Lichen planus pigmentosus; Skin phototypes.