Topical Immunotherapy of Alopecia Areata: A Large Retrospective Study

INTRODUCTION Topical immunotherapy is frequently used in the treatment of alopecia areata (AA) although few studies report long-term follow-up. Our goals were to determine the efficacy and the prognostic factors of topical immunotherapy in a large cohort of patients with AA treated in the departments of Dermatology and Venereology of Bergamo, Como and Pavia, from 1978 to January 2016. METHODS A total of 252 patients with AA were evaluated retrospectively. RESULTS All our patients developed an allergic reaction to a 2% solution of dinitrochlorobenzene (DNCB) or squaric acid dibutylester (SADBE) or diphenylcyclopropenone (DPCP). No patients discontinued therapy because of side effects. In total 112 patients (44.05%, p < 0.001) had a good response. Statistical analysis revealed that the main prognostic factors influencing the clinical results were the severity of hair loss at the beginning of therapy, the duration of AA, a history of atopy (particularly eczema), and the early development of sensitization to the three sensitizers. CONCLUSION Topical immunotherapy in patients with AA is quite effective, mostly well tolerated, and provides prolonged therapeutic benefits.