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Psoriasis Causes


Psoriasis is a common skin disorder, affecting about 7.5 million people in the United States. It causes skin cells to multiply rapidly and to accumulate on the surface of the skin. These extra skin cells create thick, scaly patches called plaques. Plaques most often develop on the:

  • elbows
  • knees
  • scalp
  • lower back
  • palms of the hands
  • soles of the feet

The affected areas of skin typically appear reddened and contain dry, itchy scales. They may also be more sensitive and cause a burning or painful sensation on the skin.

If you have psoriasis, you’re probably familiar with these uncomfortable symptoms. You may also know that psoriasis is a chronic condition that can be managed with treatment, but not cured. But you may not be sure why your disorder developed in the first place or why your symptoms come and go. While the specific causes of psoriasis aren’t completely understood, learning about the possible triggers for symptoms can prevent future flare-ups and improve your quality of life.

What causes psoriasis?

The exact cause of psoriasis isn’t known. Some medical researchers have theories about why people develop psoriasis. According to the National Psoriasis Foundation, an estimated 10 percent of Americans inherit genes that increase their likelihood of getting psoriasis. Of those 10 percent, however, only about 2 to 3 percent actually develop psoriasis.

Scientists have identified about 25 gene variants that can increase risk for psoriasis. These genetic variants are believed to cause changes in the way the body’s T cells behave. T cells are immune system cells that normally fight off harmful invaders, such as viruses and bacteria. In people with psoriasis, however, T cells also attack healthy skin cells by mistake. This immune system response results in a range of reactions, including:

  • enlargement of blood vessels in the skin
  • increase in white blood cells that stimulate the skin to produce new cells more quickly than usual
  • increase in skin cells, T cells, and additional immune system cells
  • accumulation of new skin cells on the surface of the skin
  • development of the thick, scaly patches associated with psoriasis

Typically, these effects occur in response to a trigger.

What triggers psoriasis?

The symptoms of psoriasis often develop or become worse due to certain triggers. These can be environmentally or physically related. The triggers vary from person to person, but common psoriasis triggers include:

  • cold temperatures
  • drinking too much alcohol
  • smoking
  • having another autoimmune disorder, such as AIDS or rheumatoid arthritis
  • infections that cause a weakened immune system, such as strep throat
  • a skin injury, such as a cut, bug bite, or sunburn
  • excessive stress and tension
  • certain medications, including lithium, beta blockers, and anti-malarial drugs

You can identify your specific triggers by tracking when you experience psoriasis symptoms. For example, did you notice a flare-up after a stressful week at work? Did your symptoms become worse after having a beer with friends? Staying vigilant about when symptoms occur can help you determine potential psoriasis triggers.

Your doctor can also evaluate your medications and overall health to help you pinpoint possible triggers. Make sure to tell your doctor about any prescription or over-the-counter medications you may be taking. Your doctor may switch you to another medication or make a change in your dosage if they suspect your medication is causing your outbreaks. You shouldn’t stop taking any medications unless your doctor instructs you to do so.

How can psoriasis flare-ups be prevented?

While you can’t change your genes, you can prevent psoriasis flare-ups by controlling your symptoms through regular treatments. These include applying topical medications, taking oral medications, or receiving injections to reduce uncomfortable psoriasis symptoms. Phototherapy or light treatment can also reduce the incidence of psoriasis. This type of treatment involves using natural or artificial ultraviolet light to slow skin growth and inflammation.

Aside from medical treatments, making certain lifestyle adjustments can also reduce your risk for a psoriasis flare-up. These include:

Reducing stress

While stress can have a negative impact on anyone, it’s particularly problematic for people with psoriasis. The body tends to have an inflammatory reaction to stress. This response can lead to the onset of psoriasis symptoms. You can try reducing the amount of stress in your life by doing yoga, meditating, or meeting with a therapist on a regular basis.

Taking care of your skin

Injuries to the skin, such as sunburns and scrapes, can trigger psoriasis in some people. These types of injuries can usually be prevented by practicing good skin care. When doing activities that may cause skin injury, you should always take extra precautions. Use sunscreen and wear a hat when spending time outside. You should also use caution when engaging in outdoor activities and contact sports, such as basketball or football.

Practicing good hygiene

Infections are known to trigger psoriasis because they put stress on the immune system, causing an inflammatory reaction. Strep throat in particular is associated with the onset of psoriasis symptoms, especially in children. However, psoriasis flare-ups may occur after an earache, tonsillitis, or a respiratory or skin infection. These types of infections can usually be prevented with good hygiene practices. Make sure to wash your hands often throughout the day. Also avoid sharing cups and eating utensils with other people. It’s also important to clean a cut or wound properly and to keep it covered so it doesn’t get infected.

Eating a healthy diet

Being obese or overweight appears to make psoriasis symptoms worse. So it’s important to manage your weight by exercising regularly and eating a healthful diet. If you have trouble eating healthy, you may want to see a nutritionist for help. They can help you figure out how much food and which foods you should eat every day to lose weight.


Though psoriasis can’t be cured, it can be controlled. Working with your doctor to find treatments that relieve the itching and discomfort can ease psoriasis symptoms. Taking steps to identify triggers for your symptoms and limiting your exposure to these triggers can also help prevent future flare-ups. 

Content licensed from:

Written by: Rachel Nall, RN, BSN, CCRN
Medically reviewed on: Mar 24, 2016: Debra Sullivan, PhD, MSN, RN, CNE, COI

This feature is for informational purposes only and should not be used to replace the care and information received from your health care provider. Please consult a health care professional with any health concerns you may have.
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