Frontal Fibrosing Alopecia Involving the Limbs Shows Inflammatory Pattern on Histology: A Review of 13 Cases

This study reviewed 13 cases of frontal fibrosing alopecia (FFA) involving the limbs, revealing an inflammatory pattern characterized by lymphocytic folliculitis without perifollicular lamellar fibrosis. The findings were similar to early FFA in the scalp, where lichenoid inflammation and atrophy of sebaceous glands were observed, but perifollicular fibrosis was absent. The study highlighted that limb alopecia in FFA is inflammatory and permanent, lacking classic scarring features such as fibrotic tracts. The absence of perifollicular fibrosis could lead to misdiagnosis as alopecia areata, which differs in its peribulbar infiltrate and unaffected sebaceous glands. The study emphasized the importance of recognizing these histologic patterns to avoid diagnostic confusion.