Research has revealed a close immunopathological link between GPP and plaque psoriasis, and some biologics used for treating plaque psoriasis, such as anti-TNF-α antibodies, anti-IL-17A antibodies, and anti-IL-12/23 p40 antibodies, have also shown efficacy in treating GPP and have been included in the recommended treatment guidelines for GPP in Japan.1 This evidence concerns the gene IL17A and psoriasis 14, pustular.