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NHS Choices Condition

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The exact cause of psoriasis is unknown but it is known that your immune system plays a part.

Your immune system is your body's defence against disease - it produces proteins (antibodies) that attack germs and viruses.

For some reason, if you have psoriasis, one of these antibodies called T cells start attacking healthy skin cells by mistake. This triggers other immune responses that cause an increase in the production of new skin cells and also T cells.

This results in a cycle of skin cell production becoming faster and faster - skin cells are created and then die in the space of five to six days, rather than the normal 28 days. The dead skin cells then build on the surface of your skin in thick scaly patches.

Psoriasis runs in families - one in three people with psoriasis has a close relative who also has psoriasis. However, the exact role that genetics plays in causing psoriasis remains unclear.

There are three genes that are linked to psoriasis- known as SLC9A3R1, NAT9 and RAPTOR. However, a large proportion of people with these genes never develop skin problems.

Streptococcal throat infections are involved in guttate psoriasis developing, usually in children and young adults. However, most people with who have streptococcal throat infections do not develop psoriasis.

Diseases of the immune system such as the HIV infection can cause psoriasis to flare up or to appear for the first time.

Psoriasis triggers

Many people with psoriasis find that symptoms start or become worse because of a certain event - a trigger. Identifying a trigger may allow you to avoid a flare-up of psoriasis. Common triggers include:

  • alcohol,
  • smoking,
  • an injury to your skin such as a cut, scrape, insect bite, or sunburn (this is known as 'the Koebner response'),
  • stress, and
  • certain medicines like lithium, antimalarial medicines, anti-inflammatory medicines including ibuprofen, ACE inhibitors (used to treat hypertension) and beta blockers (used to treat congestive heart failure).


view information about Psoriasis on www.nhs.co.uk »

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