Unpredictable and irritating, psoriasis is one of the most baffling and persistent of skin disorders. It's characterized by skin cells that multiply up to 10 times faster than normal. As underlying cells reach the skin's surface and die, their sheer volume causes raised, red plaques covered with white scales. Psoriasis typically occurs on the knees, elbows, and scalp, and it can also affect the torso, palms, and soles of the feet.
The symptoms of psoriasis vary depending on the type...
Patches of red, inflamed skin. These are often covered with loose, silver-colored scales. These plaques may be itchy and painful. They may sometimes crack and bleed. In severe cases, they grow and merge into each other, making large areas of inflamed skin.
Fingernail and toenail problems. Your nails may change color or become pitted. They may also begin to crumble or detach from the nail bed.
Scalp problems. Patches of scales or crust may form on your scalp.
Psoriasis can also cause psoriatic arthritis. This causes pain, swelling, stiffness, and damage in your joints. About 30% of people with psoriasis get psoriatic arthritis between the ages of 30 and 50.
What Causes Psoriasis Flare-ups?
Immune system problems seem to be the underlying cause of psoriasis. But certain triggers may make your symptoms worse or cause flare-ups. They include:
Cold and dry weather. This dries out your skin, which makes your chance of having a flare-up more likely. But hot, sunny weather may help you control your symptoms.
Stress. Having psoriasis can cause stress, which can make your symptoms worse. You may even have outbreaks of symptoms during very stressful times.
Drugs. Certain drugs can cause psoriasis to flare up. These include:
Lithium, a treatment for bipolar disorder
Some beta-blockers, used to treat high blood pressure and heart disease
Infections or disease. Certain infections, such as strep throat or tonsillitis, can cause guttate or other types of psoriasis. Guttate psoriasis often starts when a person is a child or young adult. HIV can also make psoriasis worse.
Injury to the skin. In some people, injury to the skin -- including cuts, bruises, burns, bumps, vaccines, tattoos, and some skin conditions -- can cause a flare-up of psoriasis where they happen This is called Koebner's phenomenon.
Alcohol. Drinking alcohol may raise your chance of a flare-up, at least if you are a man.
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.
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.
National Institute of Arthritis and Musculoskeletal and Skin Diseases.