Plaque Psoriasis
Key points
- Psoriasis is a common skin inflammation (irritation and swelling) characterized by frequent episodes of redness; itching; and thick, dry, silvery scales on the skin.
- Psoriasis is a very common condition, with approximately 3 million Americans affected.
- The diagnosis is usually based on the appearance of the skin.
- Treatment is focused on control of the symptoms and prevention of secondary infections.
Definition
Psoriasis is a common skin inflammation (irritation and swelling) characterized by frequent episodes of redness; itching; and thick, dry, silvery scales on the skin.
Alternative Names
Plaque psoriasis
Causes, incidence, and risk factors
Psoriasis is a very common condition, with approximately 3 million Americans affected. It can appear suddenly or gradually. In many cases, psoriasis goes away and then flares up again repeatedly over time. The disorder may affect people of any age, but it most commonly begins between ages 15 and 35.
Psoriasis seems to be an inherited disorder, probably related to an inflammatory response in which the immune system accidentally targets the body's own cells. Evidence of the condition is most commonly seen on the trunk, elbows, knees, scalp, skin folds, or fingernails, but it may affect any or all parts of the skin.
Normally, it takes about a month for new skin cells to move up from the lower layers to the surface. In psoriasis, this process takes only a few days, resulting in a build-up of dead skin cells and formation of thick scales.
Psoriasis may be aggravated by injury or irritation (such as cuts, burns, rashes, insect bites). It may be severe in immunosuppressed people (like those with AIDS or undergoing chemotherapy for cancer), or those who have other autoimmune disorders (such as rheumatoid arthritis).
Medications, viral or bacterial infections, excessive alcohol consumption, obesity, lack of sunlight, sunburn, stress, general poor health, cold climate, and frequent friction on the skin are also associated with psoriasis flare-ups. The condition is not contagious.
Symptoms
- Skin patches
- Dry or red
- Usually covered with silvery scales
- Raised patches of skin
- Accompanied by red borders
- May crack and become painful
- Usually discrete, demarcated patches
- Usually located on the elbows, knees, trunk, scalp, hands or nails
- Dry or red
- Skin lesions, including pustules, cracking of skin, skin redness or inflammation
- Itching
- Small scaling dots on the skin (especially in children)
- Joint pain or aching, which may be associated with a special type of arthritis (psoriatic arthritis)
Additional symptoms that may be associated with this disease:
Written and revised by
David Cohen, M.D.
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