Topical squaric acid dibutylester (SADBE) is a contact sensitizer currently being used in the treatment of alopecia areata. It acts as an ideal immunogen because it is not found in the natural environment and is not mutagenic by the Ames test, unlike other topical sensitizers such as dinitrochlorobenzene.1
In the current literature, the population of patients treated with SADBE includes adults and children of all ages and both sexes, often with severe disease that is refractory to other forms of treatment. There have been few studies to date that critically assess the efficacy of squaric acid use in these patients. Even fewer studies have examined the criteria for beginning treatment with SADBE.
Pardasani AG, Turner E, McMichael AJ. Squaric Acid Dibutylester: Indications for Use and Efficacy in Alopecia Areata. Arch Dermatol. 2001;137(7):970-972. doi: