This is migratory arthritis causes good article. Follow the link for more information. Psoriasis varies in severity from small, localized patches to complete body coverage. Plaque psoriasis, also known as psoriasis vulgaris, makes up about 90 percent of cases.
It typically presents as red patches with white scales on top. Areas of the body most commonly affected are the back of the forearms, shins, navel area, and scalp. Guttate psoriasis has drop-shaped lesions. Inverse psoriasis forms red patches in skin folds. Erythrodermic psoriasis occurs when the rash becomes very widespread, and can develop from any of the other types. This may include pits in the nails or changes in nail color. This suggests that genetic factors predispose to psoriasis.
Diagnosis is typically based on the signs and symptoms. About 75 percent of cases can be managed with creams alone. The disease affects two to four percent of the population. Men and women are affected with equal frequency. The disease may begin at any age, but typically starts in adulthood. Psoriatic arthritis affects up to 30 percent of individuals with psoriasis.