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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

Causes of Psoriasis

We don’t know what causes psoriasis. 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.

Risk factors for psoriasis include:

  • Family history 
  • Cold climate
  • A suppressed immune system
  • Certain bacterial infections
  • Certain medications, such as beta blockers, tumor necrosis factor-alpha inhibitors and lithium

Psoriasis Symptoms

psoriasis on the arm
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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.

Diagnosis & Treatment at UVA

Your provider will examine your skin and nails. There are no blood tests, but you may have a skin biopsy to confirm your diagnosis.  

Psoriasis Treatment

We base treatment on the following:

  • Severity of the disease
  • Extent and location of the areas involved
  • Responsiveness to the treatment

Topical Treatment

Many patients respond very well to treatments applied directly to the skin. Topical treatments include:

  • Corticosteroid creams and ointments
  • Synthetic forms of vitamin D 
  • Retinoids
  • Coal tar
  • Bath solutions and moisturizers
  • Tacrolimus and pimecrolimus (especially for inverse psoriasis)

Photo (Light) Therapy

If you have psoriasis on 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 usually one of the first treatments.

If you have widespread psoriasis, your provider can use a more controlled form of artificial light treatment (UVB phototherapy). Alternatively, ultraviolet A (UVA light) and psoralen can also treat psoriasis. Psoralen, or PUVA,  is an oral or topical medication that makes the body more sensitive to light. 

Phototherapy can be very effective in controlling psoriasis but it requires frequent treatments. It may cause side effects such as nausea, headache, fatigue, burning, and itching. Both UVB and PUVA may increase your risk for squamous cell and, possibly, melanoma skin cancers.

Systemic Treatment

If you have severe psoriasis, your provider may recommend other powerful medications. They can be effective but can also have serious side effects. These include:

  • Methotrexate — a type of systemic medicine that affects the whole immune system. This cannot 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 that 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
  • Biologic agents — affect the body's immune response by targeting certain cells in the immune system that cause inflammation


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.