The typical lesion of psoriasis is a red, slightly raised plaque with fine silvery scales on it which can be flaked off. People with extensive plaques, especially on the scalp, can have an enormous amount of flaking. The plaques are found most commonly on the elbows, knees, scalp, and lower back, but there are many variations, such as plaques around the buttocks, anus, and genitalia or involving the soles of the feet and palms of the hands. Changes commonly occur in the fingernails and toenails, most commonly ridging and pitting. With the exception of a form of arthritis called psoriatic arthritis, which resembles rheumatoid arthritis, psoriasis is not associated with any serious or fatal condition.
Many sufferers live to a ripe old age, battling their psoriasis every year of their lives.
Some infections, including strep sore throat and HIV, can worsen the psoriasis in someone who already has it. People with few small plaques often need no treatment or can use a steroid, cortisone-type cream. These work better if applied under a so-called occlusive dressing. Some come in a tape which carries the drug and provides the occlusion, or plastic wrap can simply be taped over the cream. Sunlight is very effective in keeping the plaques under control, and many people with psoriasis maintain a year-round tan for this reason.