Allergic contact dermatitis in patients with frontal fibrosing alopecia: An international multi-center study.

Frontal fibrosing alopecia (FFA) mainly affects the anterior hairline and eyebrows and its etiology and associated factors remain obscure. The aim of this study was to evaluate the allergic contact dermatitis with patch test in patients with FFA. In this prospective study, 20 patients with FFA and 24 age and sex-matched healthy individuals were evaluated with patch testing. Diagnosis was made histologically, clinically and based on dermoscopic findings. Demographic data, age of onset, disease duration and FFA severity index are evaluated in all patients. Positive patch test reaction to one or more allergen was observed in 65% of patients while it was 37.5% in control group (P = .003). There was a significant difference between age (P = .006) and positive patch test results. No statistical significant difference was observed in the results of patch testing and disease duration (P = .519), menopausal status (P = .085), and FFA severity index (P = .573). Our findings suggest an association between FFA and allergic contact dermatitis. The utility of patch testing in FFA patients can explore the role of allergic etiology and may have an enormous impact on the diagnostic potential and quality of life of these patients.