The cause of psoriasis has not been identified, though there are multiple theories.  Much of the medical community considers psoriasis an immune-mediated disorder, not a true auto-immune disease.  Excessive cell production is a side-effect of T cells becoming active and moving to a deep layer of skin. This migration causes cytokines to be released through the skin causing inflammation. It can be proven that the T cells become active, but no evidence proving the reason.  Thus, for people with severe cases of psoriasis, the only viable treatment seems to be some kind of immunosuppressant.

An immunosuppressant is a drug that hinders the way the immune naturally functions. These drugs can be taken orally or by injection. There are two common types of these drugs. Biologics are systemic treatments that are animal or human protein by-products. They stop communication between cells in the immune system. Conventional systemics are combinations of synthetic components that work with the immune system to slow the production of skin cells. They are used to treat severe types of psoriasis. There are several side-effects of both types of medications. In some cases, they cause allergic reactions or skin growths or tumors.

In all cases, using immunosuppressants will decrease the body’s ability to stave off infection. Despite their effectiveness, this puts patients at risk. The level of risk varies from one individual to another based on several factors from severity of the condition to age. Though severe infections are rare, many patients report greater receptiveness to colds and every day viruses. Patients on biologics seem more susceptible to illness than those on conventional systemics. This makes flu vaccinations even more important.