Alopecia Diffusa While Using Interleukin-17 Inhibitors Against Psoriasis Vulgaris

Two cases of alopecia diffusa were reported during the treatment of psoriasis vulgaris with interleukin (IL)-17 inhibitors. While IL-17 inhibitors showed dramatic effects against psoriasis, the occurrence of alopecia was an unexpected paradoxical reaction. The study suggested that Th17 cells, which are not typically cytotoxic to hair follicles, might initiate damage that requires the presence of CD8+ cytotoxic Th1 cells to result in alopecia. The use of IL-17 inhibitors might shift the immune response to a Th1-dominant status, leading to hair follicle destruction and subsequent alopecia. Further accumulation of similar cases was anticipated.