What is Psoriasis?
The precise cause of psoriasis is unknown, but hereditary and genetic factors are important, and stress is also believed to play a part. Psoriasis does run in families, but this does not mean that every child of a parent with psoriasis will develop the condition. Psoriasis can occur at any point in the lifespan, affecting children, teenagers, adults and older people. It affects males and females equally. Psoriasis is not contagious, nor can it be transferred from one part of the body to another.
Psoriasis appears as red, scaly patches on the skin. Patches of psoriasis (or ‘plaques’) are raised red patches of skin, covered with silvery white scales. The silvery white scales are the accumulation of dead skin cells waiting to be shed. This happens because in psoriasis sufferers, the normal skin renewal process accelerates dramatically. Normally skin cells take about 21 to 28 days to replace themselves, however in psoriasis, skin cells can be replaced every two to six days. This results in an accumulation of skin cells on the surface of the skin, in the form of a psoriatic plaque. The psoriatic plaques also appear as red because of the increase in blood vessels required to support the increase in cell production.
Recent research has found that psoriasis is an autoimmune disorder, caused when certain immune cells (T cells) are triggered and become overactive. The T cells produce inflammatory chemicals, and act as if they were fighting an infection or healing a wound, which leads to the rapid growth of skin cells causing plaques to form. A trigger is required for psoriasis to develop and this could be a throat infection, injury to the skin, certain drugs and physical or emotional stress.
Psoriasis can range in appearance from mild to severe. The plaques can appear in a variety of shapes and sizes, from a few millimetres to several centimetres in diameter. Psoriasis takes the following forms:
•Common plaque psoriasis (psoriasis vulgaris) – Affects around 80% of psoriasis sufferers and the plaques usually appear on the elbows, knees, lower back and scalp.
•Guttate psoriasis – plaques are small and scaly (less than 1cm in diameter) and can be numerous all over the body. Seen most often in children and teenagers and can be triggered by a throat (streptococcal) infection.
•Psoriasis in sensitive areas – the armpits and groin take on a red, shiny appearance with little or no scaling.
•Pustular psoriasis – small blisters on the hands and feet.
•Nail psoriasis – changes in the texture and appearance of the nails of the hands and feet.
•Psoriatic arthritis – About 10% of psoriasis sufferers can develop this form of arthritis. Often, though not always, seen in people with widespread psoriasis. It can affect people of all ages.
Psoriasis can affect the quality of life of sufferers, because they are embarrassed about the appearance of their skin, and normal activities, such as wearing short sleeved tops in warm weather, or going swimming, can be severely restricted. Fortunately, most people have only small amount.
