Psoriasis is one of the most common and widespread diseases of the skin, affecting about 2% of the global population.
Psoriasis can develop at any age, but typically first occurs in adolescence or from the age of forty. It is a chronic, non-contagious disease that primarily affects the skin.
Although psoriasis is non-hereditary, people may be genetically predisposed to its development. However, this does not necessarily mean that they will actually suffer from the disease. How exactly psoriasis develops is still unclear. It is assumed that a number of different factors may cause or influence its development, and for this reason it is commonly referred to as a multifactorial disease. A combination of a genetic predisposition and environmental factors may cause or aggravate the disease. Possible triggers include:
These factors may also aggravate the symptoms.
95% of psoriasis sufferers have the classic symptoms of psoriasis (psoriasis vulgaris). The disease is characterised by round or oval scaly, red patches of skin. These may appear on any part of the body, but most commonly occur on the scalp, the elbows, the extensor surfaces of the knees, around the cruciate ligaments and in the buttock crease.
These patches develop when the outer skin layer is regenerated too quickly. In healthy skin, this process takes 28 days but the cells in these patches are regenerated in just 8 days. The incomplete keratinisation process leads to the development of silvery patches. The affected areas of skin dry out and the skin may crack or bleed.
In most cases, the disease periodically flares up and subsides. Sufferers may experience severe itching during flare-ups.
In the most common type of psoriasis, silvery red patches may appear anywhere on the body. These patches or plaques give this type its name – plaque psoriasis. Some patients may also have psoriasis of the finger and toenails (nail psoriasis), with pitting (small pinprick holes) on the nail surface, discolouration (oil spots) and lifting of the nailbed.
This type of psoriasis is often very itchy and commonly occurs after a bacterial infection. It is charactersied by multiple, small psoriatic lesions (guttate means dot-like).
In this rare and unusual type of psoriasis, pus-filled blisters form on reddened areas of skin. They may form on discrete parts of the body (such as the palms of the hand and soles of the feet) or cover the entire body.
Nail changes may occur in all types of psoriasis. In roughly half of all cases, these changes occur in the fingernails, in slightly fewer in the toenails.
Approximately 20% of psoriasis sufferers also have painful arthritis, an inflammatory rheumatic disease. Psoriatic arthritis is a form of spondyloarthropathy and may affect both the spine and any peripheral joint or tendon attachment point.
There is as yet no cure for psoriasis. However, appropriate treatment to alleviate the symptoms can help sufferers largely lead a normal life.
Finding the appropriate treatment is not always easy. What works with one sufferer does not necessarily work with others.
The choice of treatment depends on the following factors:
The following treatments are available for psoriasis and can also often be combined: