Some medicines used to treat high blood pressure, heart disease, arthritis, and mental disorders can trigger psoriasis.
Common drugs like ACE inhibitors, beta-blockers, and lithium can cause flare-ups. So can malaria pills like Plaquenil and hydroxychloroquine, and NSAIDs. Steroid pills such as prednisone control flares, but they may make the condition worse after long-term use.
Talk to your doctor if your medication is irritating your skin.