Follicular Melanocytes in Frontal Fibrosing Alopecia: An Immunohistochemical Study With Trichoscopic Correlation.

BACKGROUND

Frontal fibrosing alopecia (FFA) is a scarring alopecia that affects the frontotemporal hairline. Clinically, it may develop with cutaneous hypopigmentation of the affected areas, which has been associated with a reduction in the epidermal melanocyte count. In trichoscopy, peripilar white halos can be observed, which have been associated with fibrosis in other scarring alopecias.

OBJECTIVE

To evaluate the trichoscopic, histopathological and immunohistochemical characteristics of the peripilar white halos in FFA patients.

MATERIALS AND METHODS

We conducted a descriptive cross-sectional study that included 12 patients with FFA presenting peripilar white halos. Two 2-mm punch trichoscopy-guided biopsies were performed in all patients, one fragment for vertical section and another for horizontal section. The vertical sections were stained with Fontana-Mason and Melan-A.

RESULTS

On trichoscopic examination, peripilar white halos ≤ 1 mm in size were observed on the affected scalp. In vertical sections, a reduction in basal melanin pigmentation and a decrease in the melanocyte count in the upper segment of the hair follicle were observed with Fontana-Masson staining and Melan-A immunostaining, respectively.

LIMITATIONS

The small sample size and absence of a control group.

CONCLUSION

This study shows follicular melanocyte involvement in FFA, and this finding may be associated with the peripilar white halos observed in trichoscopy.