Psoriasis is an autoimmune disease affecting the skin and joints. When it affects the skin it commonly appears as red scaly elevated patches called plaques. Psoriasis plaques frequently occur on the elbows and knees, but can affect any area of skin including the scalp and genital area. Psoriasis can vary in severity, from minor localised patches to extensive or even complete skin coverage. Fingernails and toenails are often affected. This is called psoriatic nail dystrophy. Psoriasis can also cause inflammation of the joints. This is known as psoriatic arthritis. Psoriatic arthritis can affect any joint but is most common in the joints of the fingers and toes. This can result in a sausage-shaped swelling of the fingers and toes known as dactylitis. Psoriatic arthritis can also affect the hips, knees and spine. This is known as spondylitis. Psoriasis affects both sexes equally, occurs at all ages and is prevalent in 2-3% of the Western populations. Several factors are thought to aggravate psoriasis. These include stress and excessive alcohol consumption. Individuals with psoriasis may also suffer from depression and loss of self-esteem. As such, quality of life is an important factor in evaluating the severity of the disease. There are many treatments available but because of its chronic recurrent nature psoriasis is a challenge to treat. Psoriasis is driven by the immune system, especially involving a type of white blood cell called a T cell. Normally, T cells help protect the body against infection and disease. T cells help create scabs over wounds. In the case of psoriasis, T cells are put into action by mistake and become so active that they trigger other immune responses, which lead to inflammation and to rapid turnover of skin cells. Epidermal cells then build up on the surface of the skin, forming itchy patches or plaques. Specialist dermatologists generally treat psoriasis in steps based on the severity of the disease, size of the areas involved, type of psoriasis, and the patient's response to initial treatments. This is sometimes called the "1-2-3" approach. In step 1, medicines are applied to the skin (topical treatment). Step 2 uses ultraviolet light treatments (phototherapy). Step 3 involves taking medicines by mouth or injection that treat the whole immune system (called systemic therapy). Over time, affected skin can become resistant to treatment, especially when topical corticosteroids are used. Also, a treatment that works very well in one person may have little effect in another. Thus, doctors often use a trial-and-error approach to find a treatment that works, and they may switch treatments periodically (for example, every 12 to 24 months) if a treatment does not work or if adverse reactions occur. In conclusion, Psoriasis is a chronic condition. There is currently no cure. People often experience flares and remissions throughout their life. Controlling the signs and symptoms typically requires lifelong therapy. Disclaimer - The information presented here should not be interpreted as medical advice. If you or someone you know suffers from Psoriasis, please consult your physician for the latest treatment options. Permission is granted to reprint this article as long as no changes are made, and the entire resource box is included.