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How do you get psoriasis and is it contagious?

Medically reviewed by Sally Chao, MD. Last updated on Jan 23, 2024.

Official answer


A person’s genes and immune system play a role in the development of psoriasis. It is not contagious.

  • The process behind the overproduction of skin cells in people with psoriasis has to do with a breakdown in the immune system. The immune system normally uses white blood cells to fend off sickness and attack bacteria and viruses. When you have psoriasis, your white blood cells mistakenly attack your skin cells, prompting your body to make more of them, where they collect on the surface of your skin. It is not fully understood why some people develop psoriasis or what causes the immune system to malfunction in this way.
  • Genetics also can play a role, as psoriasis runs in families, and certain genes increase your risk of developing psoriasis. However, not everyone who has these genes gets psoriasis, and some people who have psoriasis do not seem to have a genetic predisposition, which is why environmental factors may also play a role.

Psoriasis is not contagious. It is not a bacterial infection that can be spread. You cannot get it by touching or being close to someone who has psoriasis.

With psoriasis, new skin cells are generated too rapidly. Normally, skin cells are made deep within the skin, and then rise to the surface as dead skin is shed. This process usually takes weeks.

If you have psoriasis, this process takes days instead of weeks. All of these extra skin cells pile up on the surface of the skin, creating the thick, scaly patches that are associated with the most common form of psoriasis — called plaque psoriasis.

Psoriasis is often a life-long condition, but you may go through periods with little or no symptoms. When symptoms begin, reemerge or get worse, these are called “flare-ups.” Anyone can develop psoriasis, but it commonly begins between ages 15 and 35.

There are a variety of potential “triggers” that may cause psoriasis to appear for the first time, or induce a flare-up if you already have psoriasis, including:

  • Stress
  • Skin injury, such as a cut or bad sunburn
  • Infection, such as strep throat
  • Some medications, including lithium, prednisone and hydroxychloroquine
  • Weather, especially cold, dry weather
  • Tobacco
  • Alcohol (heavy drinking)

Psoriasis triggers are different for everyone. There is no definitive way to prevent psoriasis, but identifying and avoiding your triggers can help reduce future flare-ups.

Related Questions

  1. American Academy of Dermatology Association. Psoriasis: Causes. Available at: [Accessed November 19, 2020].
  2. U.S. National Library of Medicine. Psoriasis. Updated July 13, 2018. Available at: [Accessed November 19, 2020].
  3. American Academy of Dermatology Association. Psoriasis: Overview. Available at: [Accessed November 19, 2020].
  4. American Academy of Family Physicians. Psoriasis. Updated July 25, 2019. Available at: [Accessed November 19, 2020].

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