It occurs when the immune system mistakes the skin cells as a pathogen, and sends out faulty signals that speed up the growth cycle of skin cells.

Psoriasis is not contagious, however it has been linked to an increased risk of stroke. There are different variations of psoriasis; plaque, guttate, inverse, pustular and erythrodermic. The most common form is plaque psoriasis, which is commonly seen as red and white hues of scaly patches appearing on the top first layer of the skin. Some people with psoriasis however show no dermatological symptoms at all.

The cause of psoriasis is not fully known, but it is believed to have a genetic component and local psoriatic changes can be triggered by an injury to the skin. Various environmental factors have been suggested as aggravating to psoriasis, most notably stress and the withdrawal of systemic corticosteroid.

There are many treatments available, but because of its chronic recurrent nature, psoriasis is a challenge for dermatologists to treat.