Skins cells shed all the time, but in psoriasis, both dead and live cells collect on the skin’s surface, because the replacement process is so fast.
The main symptoms of psoriasis are:
- red, flaky, crusty patches, covered with silvery scales that shed easily
- intense itching and burning
According to the National Psoriasis Foundation:
- mild psoriasis covers less than 3 percent of the body
- moderate psoriasis affects between 3 and 10 percent
- Severe psoriasis covers over 10 percent of the body.
There are several forms of psoriasis.
About 80 to 90 percent of people with psoriasis have plaque psoriasis. It appears as raised, inflamed, red lesions, covered by silvery, white scales, generally on the elbows, knees, scalp, and lower back.
Inverse psoriasis appears in the armpits, the groin, under the breasts, and in other skin folds such as around the genitals, and the buttocks. It first appears as red lesions, generally without the scale associated with plaque psoriasis. It may appear smooth and shiny.
Irritation from rubbing and sweating can make it worse, because of its location in skin folds and tender areas. It is more common in people who are overweight and in those with deep skin folds. It can affect the genital area.
Erythrodermic psoriasis is a particularly inflammatory form that can affect large parts of the body surface with a fiery redness. Erythema means reddening.
It usually appears on people with unstable plaque psoriasis, where lesions are not clearly defined. There may also be exfoliation, or shedding of the skin, severe itching, and pain.