Psoriasis is a chronic, inflammatory skin disease. Knees, elbows, scalp, trunk, and nails are the most commonly affected areas. There are several types of psoriasis:
- Plaque — inflamed patches of skin topped with silvery, white scales (most common type)
- Guttate — small dot-like lesions
- Pustular — weeping lesions and intense scaling
- Inverse (intertriginous) — inflamed patches of skin in body folds (armpits, groin, under breasts)
- Erythrodermic — intense sloughing and inflammation of nearly the entire skin
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Causes of Psoriasis
The cause of psoriasis is unclear. Signals from a defect in the immune system may result in an overgrowth of skin cells. Because the cells grow faster than they can be shed, they pile up on the skin's surface. The excess skin cells are thought to cause the silvery white scales that are characteristic of plaque-type psoriasis.
A risk factor is something that increases your chance of getting a disease or condition. Risk factors for this condition include:
- Family history of psoriasis
- Cold climates
- Suppression of the immune system, including
- Certain bacterial infections
- Certain medications, such as beta blockers, tumor necrosis factor-alpha inhibitors, and lithium
The red, thickened, and rough patches of psoriasis may occur anywhere, but are commonly found on the scalp, elbows, knees, palms, and soles. Other symptoms include:
- Silvery white scales
- Pitted or dented fingernails and/or toenails
- Red lesion in folds of skin
- Joint pain suggesting arthritis
The skin may also be sore, burning, or itchy depending on the type of psoriasis.
The rashes may come and go.
The doctor will ask about your symptoms and medical history. A physical exam will be done including an examination of your skin and nails will be examined. There are no specific blood tests or diagnostic procedures for psoriasis. Sometimes a skin biopsy will be done to confirm the diagnosis.
Treatment is based on:
- The severity of the disease
- The extent and location of the areas involved
- Responsiveness to the treatment
Many patients respond very well to treatments applied directly to the skin. Topical treatments include:
- Corticosteroid creams and ointments (most common treatment)
- Synthetic forms of vitamin D and retinoids (calcipotriene ointment)
- Retinoids (tazarotene gel 0.05 and 0.1%)
- Coal tar preparations
- Bath solutions and moisturizers
- Tacrolimus and pimecrolimus (especially for inverse psoriasis)
Photo (Light) Therapy
If psoriasis covers more than 30% of the body, it is difficult to treat with topical medications alone. Daily, short, nonburning exposure to sunlight clears or improves psoriasis in many people. Sunlight is often included among initial treatments.
A more controlled form of artificial light treatment (UVB phototherapy) is often used in cases that are more widespread. Alternatively, psoriasis can be treated with ultraviolet A (UVA light) and psoralen. Psoralen is an oral or topical medication that makes the body more sensitive to light. This treatment is known as PUVA.
Phototherapy can be very effective in controlling psoriasis but it requires frequent treatments. It may cause side effects such as nausea, headache, and fatigue, burning, and itching. Both UVB and PUVA may increase the person's risk for and, possibly, .
For more severe types of psoriasis, doctors may prescribe a number of other powerful medications, which can be effective, but are associated with side effects that are more serious. These include:
- Methotrexate — a type of systemic medicine that affects the whole immune system; should not be taken by pregnant women, women planning to become pregnant or by their male partners
- Cyclosporine — another type of systemic medicine that suppresses the immune system to slow the turnover of skin cells; should not be taken by pregnant or breastfeeding women
- Hydroxyurea — less toxic than methotrexate or cyclosporine, but may be less effective
- Systemic retinoids — Compounds with vitamin A-like properties taken internally, can cause birth defects, (women must diligently protect themselves from pregnancy for several years after completing treatment) and are often combined with phototherapy to increase effectiveness and protection against squamous skin cancer
- Newer medicines include biologic agents, which affect a part of the body's immune response by targeting certain cells in the immune system that cause inflammation, including:
Avoiding physical trauma to the skin, infections, and cold, dry temperatures may help reduce flare-ups in people with the condition. Your doctor may advise you to avoid certain foods if they appear to make your psoriasis worse.
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Content was created using EBSCO’s Health Library. Edits to original content made by Rector and Visitors of the University of Virginia. This information is not a substitute for professional medical advice.