What is a Psoriasis trigger or flare-up?

A trigger is when something irritates the Psoriasis, causing a flare-up of symptoms. Some typical triggers are: infections such as strep throat or skin infections, injury to the skin such as a cut, scrape or sunburn, stress, smoking, heavy alcohol consumption, vitamin D deficiency and certain medications such as lithium, beta blockers, antimalarial drugs, and iodides.