A Potential Role for IL-4 and IL-13 in an Alopecia Areata–Like Phenotype: A Clinical Perspective

The document from 2020 presented three clinical cases that suggested the cytokines IL-4 and IL-13, associated with the T helper type 2 (Th2) pathway, may contribute to an alopecia areata (AA)-like phenotype. Traditionally, AA was considered a T helper type 1 (Th1)–mediated disorder. However, these cases indicated that Th2 activity could also play a role in AA. The first patient, a 19-year-old female with a food allergy, showed hair regrowth after eliminating the allergenic food from her diet. The second patient, a 26-year-old female with food and environmental allergies, experienced hair regrowth after treatment with tofacitinib. The third patient, a 13-year-old female with atopic dermatitis and alopecia totalis, showed hair regrowth after treatment with dupilumab, a monoclonal antibody against IL-4 that downregulates Th2 activity. These cases suggested that IL-4 and IL-13 may contribute to the immunopathogenesis of an AA-like phenotype in some patients.