IL17A and psoriasis: Anti-IL-17A secukinumab (Mrowietz et al., 2019) and anti-IL-23 guselkumab (Terui et al., 2018) have yielded disappointing results in the treatment of pustular psoriasis, achieving only Palmoplantar Psoriasis Area and Severity Index 75 in 26.6% and 11.5–20.4% of patients at week 16, respectively.