“Normal‐appearing” scalp areas are also affected in lichen planopilaris and frontal fibrosing alopecia: An observational histopathologic study of 40 patients

Lichen planopilaris (LPP) and frontal fibrosing alopecia (FFA) are lymphocyte-mediated scarring alopecias which clinically affect primarily the anterior and mid-scalp. However, unaffected scalp areas have not yet been investigated in a systemic manner. In this study, we assessed histopathologic changes in affected and unaffected scalp in both diseases and healthy control subjects and compared these findings with clinical signs and scalp symptoms. We have demonstrated that "normal-appearing" scalp that is devoid of clinical lesions of LPP and FFA showed lymphocytic perifollicular inflammation around the isthmus/infundibulum areas in 65% of biopsy specimens, perifollicular fibrosis in 15% and mucin deposits in 7.5% of the cases. None of these findings were found in control samples. No direct correlation was found between the degree of histopathological inflammation, scalp symptoms and clinical lesions in the corresponding affected scalp areas. This preliminary study suggests that both diseases may be more generalized processes which affect the scalp and therefore need systemic or total scalp therapy.