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What is Psoriasis?

Psoriasis is a common chronic inflammatory skin disease most commonly characterized by well-demarcated, erythematous plaques (raised red patches) with silver scales. Psoriasis is usually diagnosed clinically, based on typical appearance on typical sites.

Psoriasis occurs in a variety of clinical forms. The major categories include:

  • chronic plaque psoriasis
  • guttate psoriasis
  • pustular psoriasis
  • erythrodermic psoriasis
  • inverse psoriasis
  • nail psoriasis

Common signs and symptoms include multifocal or generalized areas of skin redness, flaking and itch. An uncommon form of psoriasis may also develop pustules.

Typical sites of psoriasis are the extensor surfaces of the body (knees, elbows). Psoriasis affecting the flexural sites (axillae, elbows, behind the knees, groin folds) is called inverse psoriasis.

Nail psoriasis often involves thickening, brittleness, staining, pitting and detachment of the nail plates.

When psoriasis affects your joints, you may experience joint pain and stiffness. This is usually worse at rest and improves with movement.

When to seek medical advice

See your doctor if:

  • You are so uncomfortable with the condition that it affects your quality of life
  • There is widespread involvement
  • You have tried self-care steps without success
  • You are experiencing persistent joint pain and/or stiffness
Treatment and drugs

Treatment for psoriasis varies depending on the type, location and severity. Potential precipitating factors should also be elicited and addressed accordingly. These include:

  • drugs e.g. beta-blockers, anti-malarials, withdrawal of oral or potent topical corticosteroids
  • stress
  • environmental factors e.g. heat
  • trauma (Köbner phenomenon) - physical, chemical, electrical, surgical, infective and inflammatory
  • infection e.g. streptococcal throat infection
  • HIV infection
  • metabolic e.g. hypocalcaemia (in pustular psoriasis)

Your doctor will assess your condition carefully before recommending the appropriate treatment. Regular use of moisturizers is important in reducing itching and scaling.

Mild psoriasis is usually treated with topical creams, ointments or scalp solutions. These include coal tar, dithranol, salicylic acid, corticosteroids, or vitamin D-type drugs (calcipotriol or calcitriol).

More severe psoriasis may require phototherapy with ultraviolet A (UVA) or B (UVB) light, which requires coming two to three times a week for treatment.

Severe psoriasis not responding to the above may require prescribing oral tablets such as methotrexate, acitretin and cyclosporin. Unfortunately, oral medications can cause side effects such as bone marrow damage, liver damage and kidney damage, and require regular blood tests to detect these side effects.

New injectable biologic agents which are safe and effective are also available for patients who do not respond to conventional therapy.

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