Cold and dry weather. Such weather can dry out your skin, which makes the chances of having a flare-up worse. In contrast, hot, sunny weather appears to help control the symptoms of psoriasis in most people.
Stress. Having psoriasis can itself cause stress, and patients often report that outbreaks of symptoms come during particularly stressful times.
Trauma to the skin. In some people with psoriasis, trauma to the skin -- including cuts, bruises, burns, bumps, vaccinations, tattoos, and other skin conditions -- can cause a flare-up of psoriasis symptoms at the site of the injury. This condition is called "Koebner phenomenon."
Alcohol. Using alcohol may increase the chances of psoriasis flare-ups, at least in men.
Smoking. Some experts think that smoking can worsen psoriasis symptoms.
SOURCES: Bruce E. Strober, MD, PhD, associate director of dermatopharmacology, department of dermatology, New York University School of Medicine; co-director, Psoriasis and Psoriatic Arthritis Center; consultant for Amgen, Biogen, Genentech, Fujisawa, and 3M. Jeffrey M. Weinberg, MD, director, Clinical Research Center, St. Luke's-Roosevelt Hospital Center, New York City; assistant clinical professor of dermatology, Columbia University College of Physicians and Surgeons; consultant for Amgen and Genentech. National Institute of Arthritis and Musculoskeletal and Skin Diseases. American Academy of Dermatology. American Academy of Dermatology, PsoriasisNet. National Psoriasis Foundation. Abel, E. ACP Medicine, April 2005.