Severe Pustular Lesions Induced by Topical Immunotherapy with Squaric Acid Dibutylester for Alopecia Totalis

The document reported two cases of severe pustular reactions in patients with alopecia totalis following topical application of squaric acid dibutylester (SADBE). Both patients, who had allergic conditions, developed itchy erythema and pustular lesions after SADBE application, requiring treatment with oral prednisolone. The first case involved a 41-year-old female who initially reacted to 0.05% SADBE but later showed improvement with 0.01% concentration over 9 months. The second case involved a 39-year-old female who reacted to 0.001% SADBE. The study suggested that cytokine imbalances and Th17 cells might contribute to the severe pustular reactions, and it emphasized the need for caution in patients with allergic predispositions undergoing contact immunotherapy.