To study the effect of fexofenadine on extensive alopecia areata (AA), we evaluated retrospectively 121 patients with AA having alopecia in more than 50% of the scalp and followed them for at least 6 months. Patients were treated by immunotherapy using diphenylcyclopropenone or squaric acid dibutylester with or without oral fexofenadine. The regrowth score was estimated as decrease of Severity of Alopecia Tool (SALT) score. In AA with atopic background (atopic AA), the mean regrowth score of the fexofenadine group was 1.333 (n = 33) and that of the control 0.471 (n = 34). The fexofenadine group showed significantly better regrowth than control by Mann–Whitney's U-test (P = 0.00213). In non-atopic AA, the mean regrowth score of the fexofenadine group was 1.303 (n = 33) and that of the control 1.048 (n = 21). There was no significant difference by Mann–Whitney's U-test (P = 0.872). Together, fexofenadine is a helpful reagent in the treatment extensive atopic AA with contact immunotherapy.