Psoriasis is a chronic autoimmune disease that mainly affects the skin. It is non-contagious. A reddish, scaly rash - often referred to as red, scaly patches - is commonly found over the surfaces of the scalp, around or in the ears, the elbows, knees, navel, genitals and buttocks.
The scaly patches, also known as psoriatic plaques, are areas of inflammation and excessive skin production. Skin quickly builds up in the affected area, because skin production is faster than the body’s ability to shed it. Areas with psoriatic plaques take on a silvery-white appearance.
Unlike eczema, psoriasis is more commonly found on the extensor aspect of a joint.
Psoriasis varies in severity - some patients may only have minor localized patches, while others are affected all over the body. Psoriatic nail dystrophy is common among patients with psoriasis - where the fingernails and toenails are affected. Psoriasis may also result in inflammation of the joints, as may be the case with psoriatic arthritis, which affects approximately 10% to 15% of all psoriasis patients.
Experts are not sure what causes psoriasis. Most believe there is a genetic component that can be triggered by a prolonged injury to the skin. Excessive alcohol consumption, smoking, mental stress, and withdrawal of systemic corticosteroid medications are said to be factors that may aggravate psoriasis.
According to the National Health Service, UK, approximately 2% of the British population is affected by psoriasis. People with psoriasis most commonly develop symptoms between the ages of 11 and 45 years. However, it can start at any age.
The human body produces new skin cells at the lowest skin level. Gradually those cells move up through the layers of skin until they reach the outermost level, where they eventually die and flake off. The whole cycle - skin cell production to skin death and flaking off - takes between 21 and 28 days. In patients with psoriasis, the cycle takes only between 2 to 6 days; resulting in a rapid buildup of cells on the skin’s surface, causing red, flaky, scaly, crusty patches covered with silvery scales, which are then shed.
Psoriasis is a chronic condition - it is long lasting. Some people have periods with no symptoms, while others live with signs and symptoms all the time. For some people psoriases can be seriously disabling.
Although there is no current cure for psoriasis, there are treatments that can help with the symptoms.
According to Medilexicon's medical dictionary:
Psoriasis is “A common multifactorial inherited condition characterized by the eruption of circumscribed, discrete and confluent, reddish, silvery-scaled maculopapules; the lesions occur predominantly on the elbows, knees, scalp, and trunk, and microscopically show characteristic parakeratosis and elongation of rete ridges with shortening of epidermal keratinocyte transit time due to decreased cyclic guanosine monophosphate.”
The word “psoriasis” comes from the Greek word psoriasis, meaning “being itchy”.