Patchy Frontal Fibrosing Alopecia: Description of an Incomplete Clinical Presentation.

We describe 6 incomplete cases of frontal fibrosing alopecia (FFA). All patients were postmenopausal women. Their average age was 60 years; 2 of the women were Caucasian, and the remaining 4 women were of a mixed ethnicity. The disease duration ranged from 3 to 17 years. The patients' lesions presented as irregular alopecic plaques in the frontal and/or temporal regions, with few signs of perifollicular inflammation, slow progression, and progressive loss of the vellus hair in the frontal area. Loss of the eyebrows, facial hyperpigmentation, and loss of the body hair were observed in 3 patients, 1 patient, and 2 patients, respectively. Localized pruritus and dysesthesia were reported in 5 patients and 3 patients, respectively. Dermatoscopic examination indicated the absence of viable ostia at the centers and edges of the lesions and the absence of peripilar erythema; moreover, peripilar hyperkeratosis was less intense than it would be expected in classical cases of lichen planopilaris (LPP) and FFA. Histological examination revealed that all cases featured the presence of a perifollicular lichenoid infiltrate in the infundibulum and isthmus as well as concentric areas of fibrosis. All samples were subjected to direct immunofluorescence (DIF), which produced negative results. FFA has been recently diagnosed and is considered a subtype of LPP. FFA can present with incomplete clinical manifestations, a histology similar to LPP, and negative DIF findings. The correct diagnosis of FFA-associated lesions is critical for providing appropriate treatment, developing prognostic definitions, and excluding other types of scarring and nonscarring alopecia. The diagnosis of incomplete FFA is essential to avoid diagnostic and therapeutic errors.