Squaric acid dibutyl ester for the treatment of alopecia areata: A retrospective evaluation.

Squaric acid dibutyl ester (SADBE) as topical immunotherapy is a good alternative in patients with refractory alopecia areata. In this study, we aimed to evaluate the effectiveness of SADBE treatment in alopecia areata (AA) and alopecia totalis/alopecia universalis (AT/AU) patients and determine the prognostic factors affecting treatment response. Data obtained from 34 (AA/AT/AU) patients treated with SADBE were analyzed retrospectively. Of the 34 patients, 16 (47.1%) were female and 18 (52.9%) were male. Sufficient responses were obtained in 19 (55.9%) patients. About 9 of the 19 patients (47.4%) with sufficient response reached a cosmetically acceptable level. As the severity of disease subsided, response to treatment increased. A better response was obtained when the disease onset in the spring and winter. Patients with a disease duration between 1 and 5 years responded better to the SADBE treatment compared to those with a disease shorter than 1 year and longer than 5 years. Severity of the disease, onset season of the disease, number of flares, duration of disease, and low levels of vitamin D in adult patients were observed to affect the SADBE response negatively.