Psoriasis is a common condition which triggers inflammation of the skin. It typically develops as patches (plaques) of red, scaly skin.
Psoriasis is not due to an infection. You cannot pass it on to other people and it is not cancerous.
Once you develop psoriasis it tends to come and go throughout life and a flare-up can occur at any time. The frequency of flare-ups varies and there may be times when psoriasis clears for long spells but, for some people, flare-ups often occur.
The severity of psoriasis varies greatly. In some people, it is mild with a few small patches which are barely noticeable. In others, there are many patches of varying size. For most people, the severity is somewhere between these two extremes.