Treatment of alopecia areata with squaric acid dibutylester.Arch Dermatol. 1987 Aug; 123(8):1036-41.AD
Fourteen of 18 patients with extensive alopecia areata completed a course of weekly treatments with the topical allergen squaric acid dibutylester in acetone. The concentration of squaric acid was varied as needed to maintain a moderate dermatitis. Only one area of alopecia was treated in each patient until marked hair growth occurred. The remainder of the scalp was then treated. Four patients (28.5%) had complete regrowth of hair during treatment; one of these patients had recurrent alopecia after stopping treatment. Ten patients (71.4%) were treatment failures. Of these ten failures, seven developed a moderate dermatitis and hair regrowth but experienced recurrent alopecia with continued treatment. One patient failed to maintain an adequate persistent dermatitis, and two failed to grow any hair despite the presence of dermatitis. Successful results in these patients correlated with (1) a duration of alopecia of less than two years, (2) the development of a moderate dermatitis within three weeks of starting treatment, (3) persistent hair growth within two months of developing dermatitis, and (4) an age of 16 years or older.