Psoriasis arthritis and other types
Most severe forms of psoriasis
Some forms of psoriasis are more severe and particularly resistant to treatment. These are pustular psoriasis, erythrodermic psoriasis and psoriatic arthritis. These should receive very careful medical treatment, in collaboration with dermatologists.
We talk about psoriasis universalis when lesions are present over the entire skin. This form of psoriasis is quite rare.
Psoriasis may appear primarily at any age, but there are two peak onset periods; during childhood/early adulthood (early onset psoriasis) and after age 40 (late onset) (1). There is strong evidence for a genetic predisposition to psoriasis, in particular to childhood psoriasis. It is estimated that 71% of patients with childhood psoriasis have a positive family history (2).
There are multiple forms of psoriasis and they are often distinguished based on the location and appearance of the lesions. The presence and distribution of psoriatic plaques is highly variable; some people suffer from a single plaque of psoriasis on a specific part of their body, whereas others suffer from psoriasis all over their bodies.
Psoriasis is accompanied by itching in 60% to 70% of cases (3).
There is to date no permanent cure for psoriasis and eruptions often recur. However, most treatments are related to significant improvements in quality of life.
Classification according to type of lesion?
Some dermatologists believe that the term "psoriasis" in fact covers six or seven different conditions, which in the future may be distinguished from each other and treated separately. The effect of the drugs that are available today (e.g. local and systemic treatments) is to clear the psoriatic plaques and to prevent relapse.
Psoriasis is classified according to the type of lesion into the following subgroups
Plaque psoriasis (psoriasis vulgaris)< | 
