It most often shows up on the torso, limbs and scalp. Pustular psoriasis is blisters that can leak. Inverse psoriasis most often appears in the folds of the skin near the genitals, under the breasts or in the arm pits. The outbreak is usually intensely red and inflamed. It will be sensitive to sweating or friction.
Erythrodermic psoriasis is widespread reddening and scaling of the skin that is itchy or painful.
It is often preceded by another insult to the skin such as a sunburn or a drug related rash. Causes Psoriasis is now believed to be an auto immune disease. That means the body turns on itself in some way. It is also believed to have a genetic component. About one third of the people with the condition have relatives with it.