Abstract: 【Abstract】 Alopecia areata （AA） is a common inflammatory and non-scarring hair loss condition with unknown pathogenesis, and relapses are common in some patients. Evidence has demonstrated that allergy takes part in the early onset, severe condition, recurrence, and prolonged process in AA. Allergy to dust mites may be one of the reasons for refractory severe AA, especially in childhood, possibly due to the predominance of T helper type 2 (Th2) immune response. Desensitization can suppress the Th2 immune response, alter the immune balance, and reduce disease severity during AA relapses. In addition, high IgE levels may predict favorable efficacy of dupilumab in AA patients before treatment, while high interleukin-4 levels may predict the ineffectiveness of topical immunotherapy with diphenylcyclopropenone, which works by antagonizing Th1 immune response. Therefore, serum total IgE, specific IgE to dust mites, and interleukin-4 can be considered as biomarkers, revealing the predominance of Th2 immune response in AA patients. This article focuses on the relationship between allergy and AA, as well as the role of anti-allergic reactions and desensitization in the treatment of AA, aiming to provide ideas for precise and individualized treatment of AA.

Key words: Alopecia areata, Anaphylaxis, Th2 cells, Immunoglobulin E, Interleukin-4, JAK inhibitors, Type Ⅱ inflammatory response, Th2-mediated immune response, Innate lymphoid cells