The present invention relates to a therapeutic agent for pustular psoriasis or psoriatic erythroderma that is administered to a psoriasis patient that has been administered with an anti-TNF-alpha antibody, comprising an IL-17RA antagonist as an active ingredient； and to a therapeutic agent for psoriasis that is administered to a psoriasis patient that cannot be treated with an anti-TNF-alpha antibody, comprising an IL-17RA antagonist as an active ingredient. In addition, the present invention also relates to a method for the treatment of pustular psoriasis or psoriatic erythroderma, comprising administering an IL-17RA antagonist to a psoriasis patient that has been administered with an anti-TNF-alpha antibody； and to a method for the treatment of psoriasis, comprising administering an IL-17RA antagonist to a psoriasis patient that cannot be treated with an anti-TNF-alpha antibody.
