Psoriasis Causes and Triggers

The exact cause of psoriasis is unknown, although scientists believe that the immune system and genetic factors are involved. It's thought that at lease 10% of the general population inherits one or more genetic mutations which create a predisposition to psoriasis. In order for a person to develop psoriasis, there must be a combination of genes that predispose to psoriasis along with exposure to specific external trigger factors.

Your immune system protects your body against disease and produces antibodies that attack germs and viruses. However, with psoriasis, antibodies called T cells, start to attack healthy skin cells by mistake. The immune system responds by increasing the production of new skin cells. Normally skin cells are created and die in 28 to 30 days, but with psoriasis, the cycle of skin production becomes faster and faster and skin cells are created and die in five to six days. This causes the dead skin cells to build up on the surface of the skin creating thick scaly patches.

Not everyone who has the specific genes goes on to develop psoriasis.  Many people find that the symptoms start or become worse because of certain triggers. The main triggers for psoriasis are:

  • Alcohol. Even though psoriasis may be aggravated by excessive alcohol, the role it plays is uncertain. It could be that the toxic effect of alcohol compromises the liver's ability to remove poisons and toxins from the body effectively. Another possibility is that alcohol can cause the body to become dehydrated, thereby making the skin worse. Alcohol can also cause a deficiency in the antioxidant vitamins A and E which may lead to oxidation damage to skin cells.

  • Smoking. Research has found that heavy smokers have greater risk of triggering psoriasis. It is thought that toxins in cigarette smoke may affect the part of the immune system associated with psoriasis.

  • Streptococcal bacteria. It is thought that a streptococcal bacterium which causes tonsillitis or ‘strep’ throat is involved in guttate psoriasis which develops commonly in children and young adults. However, most people with who have streptococcal throat infections do not develop psoriasis.

  • HIV infection. HIV infection and other diseases of the immune system can cause psoriasis to flare up or to appear for the first time.

  • Injury to the skin. Often lesions can appear in the area of an skin injury such as scars, scratches, insect bites or sunburn. This phenomenon is called the Koebner response and the symptoms can appear between 10 to 14 days after a trauma to the skin, and even up to several years later.

  • Medication. Certain medications such as beta blockers, non-steroid anti-inflammatory drugs and anti-malarial drugs can trigger psoriasis.

  • Stress. As with other skin problems, stress can worsen psoriasis and increase itching. Many people can trace their first outbreak to a time of worry and stress. Excessive and long-term stress can cause havoc on the skin as it effects all the systems of the body, especially the immune system and its important functions in protecting the body against disease.

  • Weather. Weather is a strong factor in triggering psoriasis. Cold, dry weather commonly starts a psoriasis flare-up, and hot, damp, sunny weather improves psoriasis symptoms. However, in some cases, sunshine can make the symptoms worse.

These are the main psoriasis causes and triggers. You should avoid them where possible.