Psoriasis is a persistent skin condition characterized by red, scaly patches on the limbs, trunk, scalp and other body areas. Psoriasis is not contagious.
The rash of psoriasis goes through cycles of getting better and getting worse. A “flare” is a period of rapid deterioration. Psoriasis can be unsightly, inconvenient and even painful at times.
Psoriasis can also make it difficult to sleep and do daily duties.
Psoriasis can develop on any part of the body’s skin. However, people tend to have areas that are more prone to developing lesions than others. The scalp, face, hands, feet and nails are some of the most challenging areas to treat.
Psoriatic arthritis affects between 10% to 30% of those who have psoriasis. Stiffness, discomfort and swelling of the tendons and joints and morning stiffness and overall weariness are all symptoms of psoriatic arthritis.
The severity of each psoriasis eruption varies without treatment. A mild outbreak, with small dandruff-like scales limited to one spot, could be followed by a severe outbreak with large thick plaques covering multiple parts of the body.
There are numerous methods for determining the severity of psoriasis. One simple method is to calculate how much of the body is covered, and the percentage is expressed as a proportion of the total surface area of the body.
Severity is also influenced by the type of psoriasis, the impact the illness has on a person’s quality of life and a person’s susceptibility to side effects from treatment. For example, psoriasis is generally considered severe if it covers the palms and soles because of its impact on a person’s ability to walk and perform day-to-day tasks.
Although the cause of a particular outbreak may not be known, some common triggers of psoriasis flares have been identified, including:
Normal skin cells (keratinocytes) start growing in the deepest layers of the skin (epidermis) and rise to the surface as they mature. The mature cells on the surface gradually fall off due to normal wear and strain and are replaced by younger cells underneath.
People with psoriasis have overactive T-cells that trigger an increased production of skin cells.
Under normal circumstances, the immune system’s T-cells patrol the body looking for bacteria or other foreign substances. The T-cells’ attack on such invaders is called the immune response. Many of the treatments for psoriasis, such as phototherapy, are aimed at controlling the immune response.
