Therapeutic approach with squaric acid dibutylester for steroid resistant-alopecia areata incognita: A pilot study of a single center.

Topical immunotherapy is widely used in the treatment of alopecia areata (AA). Alopecia areata incognita (AAI) is a relatively common disorder, predominantly affecting females, characterized by widespread hair thinning in the absence of typical alopecic patches. AAI can have a chronic relapsing course and in some cases can be resistant to current standard treatments. Topical immunotherapy has been used in the management of AA with encouraging results, but to date there are no literature studies reporting the efficacy of topical immunotherapy with squaric acid dibutylester (SADBE) in AAI. The aim of our study is to evaluate the efficacy and tolerance of topical immunotherapy with SADBE in AAI not responding to conventional steroid therapy. A total of 12 patients were enrolled in our Hair Disease Outpatient Service, with a proved histological diagnosis of AAI, and resistant to classical steroid therapy. Each patient underwent global photography, pull test, and trichoscopy at beginning and during the follow-ups. The efficacy of topical immunotherapy with SADBE was assessed by evaluating the changes of clinical and trichoscopic signs. Complete regrowth was achieved in 66.7% of cases (8/12), three patients remained unchanged on clinical evaluation but showed subclinical improvement on trichoscopy, whereas one patient progressed and worsened both on clinical and trichoscopic examination. All patients reported scalp diffuse mild erythema and itching the day after the application of SADBE, which were well tolerated. Three patients developed reactive cervical lymphoadenomegaly. No other side effects were observed. Topical immunotherapy with SADBE is widely used in the management of patchy AA and can be considered an effective alternative in resistant AAI, providing visible clinical and trichoscopic improvement in the majority of cases. Further studies are warranted to confirm and validate our findings.