Squaric Acid Dibutyl Ester in the Treatment of Alopecia Areata

Abstract

A controlled trial of contact allergen therapy of alopecia areata (AA) using squaric acid dibutyl ester (SADBE) was performed on 17 patients. The right side of the patient’s scalp was treated and the left side acted as an untreated control. Minimal signs of terminal hair growth were present in only 3 patients after 8–12 weeks of therapy. A majority of patients experienced adverse effects which led to the early withdrawal of 2 patients and the premature termination of the trial. We do not recommend the use of SADBE in the treatment of AA.

The therapeutic use of topical contact sensitizers in benign dermatoses

“…Twenty‐one studies using SADBE were identified, including the study which also used DPCP 150 . Two 154,155 were excluded because of small study size and five for inadequate documentation of outcome data 156–160 . The remaining 14 studies are included in Table 5. 41,42 , 150,161–171 Nineteen studies using DNCB were identified, of which two 172,173 were excluded due to small study size, two 14,174 because of duplicate publication and seven for inadequate documentation of outcome data 40,116 , 175–179 …”

The treatment of alopecia areata

“…Both SADBE and DPCP appear to be equally effective. Cosmetically acceptable regrowth in patients with severe AA (more than 40% involvement) ranged from 22 to 68%(7,8,17,45–64). Most studies have a success rate of 30 to 50%.…”

Topical Immunotherapy in Dermatology

“…A number of patients under treatment for alopecia areata may need to discontinue treatment or switch to another sensitiser because of repeated development of generalised eczema (1‐40% of patients) 9,60,64,66,68,71,86 or urticaria (2‐10% of patients) 9,67,73,80,121‐124 occurring after each application. Facial or eyelid swelling, 9,69 insomnia due to pruritus, 9,60 bullous local scalp reactions 34 and passive transfer of the sensitiser from the scalp causing hand and forearm eczema 34,57,69 are common.…”

“…The success rates quoted in numerous studies of topical immunotherapy for alopecia areata show wide variation. Total or subtotal regrowth of scalp hair such that wearing of a wig can be discontinued occurs in 4‐85% of patients treated with DCP, 9,39,60‐76 17‐70% with SADBE 33,34,77‐82 and 25‐80% with DNCB 83‐85 . Follow‐up studies are limited in number and also quote a variety of success rates.…”