The normal life cycle of skin cells is about 30 days. With psoriasis, the life cycle is 3 to 4 days in the areas of the skin affected. The attacks range from a few dry, red patches of skin covered with silvery scales to large areas with major eruptions. Areas most often affected are the elbows, knees, buttocks, and scalp. Emergency symptoms are redness and scaling affecting all the skin or bumps filled with pus.
Most people never realize they have psoriasis.
The cause of the disease is unknown. Flare-ups are often initiated by some sort of skin injury such as a cut, burn, rash, or insect bite. Certain drugs, infections, excessive alcohol consumption, being overweight, and lack of sunlight can cause outbreaks. A severe sunburn, stress, or constant friction can also irritate psoriasis. Severe psoriasis may involve the hands, feet, and nails.