Connect with others who understand.

sign up log in
About MyPsoriasisTeam

What Causes Psoriasis?

Posted on August 01, 2018
Medically reviewed by
Kevin Berman, M.D., Ph.D.
Article written by
Kelly Crumrin

Psoriasis is an autoimmune disease. Its immune system dysfunction manifests as a rash on the body or arthritis in the joints. In other words, the damage in psoriasis and psoriatic arthritis is caused by the body’s immune system attacking its own tissues.

Immune cells called T cells are responsible for attacking invaders like bacteria. In psoriasis, T cells attack the skin, and in psoriatic arthritis, they attack the joints. At the same time, the body releases cytokines and other proteins that cause inflammation — redness, swelling, pain, and heat — in areas where the disease is active.

As a result of autoimmune attacks, the body produces new skin cells at a highly accelerated rate. People without psoriasis replace their skin cells about once a month, shedding old cells as they are replaced. In psoriasis, skin cells are replaced every few days, but they cannot be shed that quickly, resulting in the build-up of thick, scaly skin seen in plaque psoriasis. The exact cause of this is not completely clear.

Risk Factors for Psoriasis

It is important to note that while science is good at finding correlations, or apparent relationships, between factors and disease, correlation does not prove that the factor causes the disease. Many risk factors for psoriasis and psoriatic arthritis have been identified and are being studied, but none have been pinpointed as the cause of psoriasis. This disease involves multiple genes (polygenic), and varying circumstances can trigger it.

Hereditary Risk Factors

Psoriasis does not appear to be directly inherited from parents in any clear genetic pattern. However, people with a relative who has psoriasis do have a higher risk for developing the disease. In fact, approximately one-third of people living with psoriasis have a relative who has also been diagnosed with psoriasis. Multiple genes are likely involved in predisposition for psoriasis, but only 2 percent or 3 percent of people with those genes will actually develop psoriasis. For someone with a genetic predisposition to psoriasis, certain changes in the immune system can lead to the development of symptoms.

People with psoriasis or psoriatic arthritis also have a higher risk for developing other chronic conditions, including type 2 diabetes, heart disease, Crohn’s disease, ulcerative colitis, and hypertension (high blood pressure). Psoriasis does not cause these conditions, but they may share genetic, environmental, and lifestyle risk factors.

Environmental Risk Factors

Smoking raises the risk for developing psoriasis. In one study of women with psoriasis, current smokers were 78 percent more likely to develop psoriasis than nonsmokers, and the risk for past smokers was 37 percent higher than for nonsmokers.

Infections, including those caused by bacteria such as streptococcus (the cause of strep throat), are known to trigger flares in people with psoriasis. Some scientists believe strep infections set off the initial immune reaction that causes psoriasis to develop. The link between an upper respiratory infection and guttate psoriasis is strongest. Strep infections affect the immune system and are known to cause similar autoimmune attacks in cases of rheumatic heart disease and some cases of kidney disease.

There is evidence of a connection between obesity (defined as having a body mass index of 30 or higher) and psoriasis. Scientists are uncertain whether being obese increases a person’s risk for developing psoriasis, or whether having psoriasis raises the risk for being obese. Both obesity and psoriasis share a common factor of inflammation. Severity of psoriasis symptoms also seems to increase as BMI increases.

Flare Triggers for Psoriasis

Psoriasis and psoriatic arthritis can go into remission, a period of minimal or no symptoms which can last for months or years until the next disease flare. Many situations can trigger flares of psoriasis and psoriatic arthritis symptoms. Some flare triggers are also being researched as possible causes of psoriasis, but most are not thought to cause the disease itself. Flare triggers are conditions that increase inflammation and stimulate autoimmune attacks, bringing new or worse psoriasis symptoms.

Triggers differ between people with psoriasis. Common triggers include:

  • Emotional stress
  • Smoking
  • Vitamin D deficiency
  • Viral or bacterial infections
  • Alcohol consumption
  • Cold weather
  • Some medications, including common blood pressure drugs
  • Skin injuries such as sunburns and cuts

Is Psoriasis Contagious?

Psoriasis is not contagious. You cannot catch it by touching someone with psoriasis, even if they are in a flare state with visible rash. Unfortunately, fear of contagion is a common stigma that socially impacts people living with psoriasis.

Condition Guide

References

  1. Treating Psoriatic Disease — National Psoriasis Foundation
  2. Psoriasis Causes and Triggers — National Psoriasis Foundation
  3. Psoriasis symptoms and causes — Mayo Clinic
  4. Related Conditions of Psoriasis — National Psoriasis Foundation
  5. Psoriasis: A Sequela of Streptococcal Infection Similar to Acute Rheumatic Fever — Clinical Microbiology
Kevin Berman, M.D., Ph.D. is a dermatologist at the Atlanta Center for Dermatologic Disease, Atlanta, GA. Review provided by VeriMed Healthcare Network. Learn more about him here.
Kelly Crumrin leads the creation of content that educates and empowers people with chronic illnesses. Learn more about her here.

A MyPsoriasisTeam Member said:

I wouldn't be surprised. I have found myself reacting to allergens and back when I took allergy shots it affected my arthritis.

posted about 1 month ago

hug

Recent articles

The month of May is very personal for us at MyPsoriasisTeam, because we honor Arthritis Awareness...

Psoriatic Arthritis: What People Don't See (Infographic)

The month of May is very personal for us at MyPsoriasisTeam, because we honor Arthritis Awareness...
The month of May is very personal for us at MyPsoriasisTeam, because we honor Arthritis Awareness...

Quiz: Is Your Psoriatic Arthritis Under Control?

The month of May is very personal for us at MyPsoriasisTeam, because we honor Arthritis Awareness...
Research has shown that certain foods can worsen psoriasis, while making dietary changes and...

Food Triggers for Psoriasis: What To Avoid

Research has shown that certain foods can worsen psoriasis, while making dietary changes and...
Nearly 90 percent of people diagnosed with psoriatic disease have trouble sleeping. In many...

Understanding and Managing “Painsomnia”

Nearly 90 percent of people diagnosed with psoriatic disease have trouble sleeping. In many...
Psoriasis in children, also called pediatric psoriasis, is a chronic (long-term) disease that...

Psoriasis in Children: Symptoms and Treatments

Psoriasis in children, also called pediatric psoriasis, is a chronic (long-term) disease that...
Though psoriasis is most common in teenagers and adults, the skin condition can affect children...

Psoriasis in Babies: Early Symptoms and Treatments

Though psoriasis is most common in teenagers and adults, the skin condition can affect children...
Many options exist for treating psoriasis, a chronic skin disease characterized by thick,...

XTRAC Laser Treatment for Psoriasis: Does It Work?

Many options exist for treating psoriasis, a chronic skin disease characterized by thick,...
People diagnosed with psoriasis or psoriatic arthritis (PsA) often experience fatigue — mental or...

Psoriasis and Fatigue: Why Am I So Tired?

People diagnosed with psoriasis or psoriatic arthritis (PsA) often experience fatigue — mental or...
The month of May is very personal for us at MyPsoriasisTeam, because we honor Arthritis Awareness...

Member Spotlight: Decades of Pain, Then Finally a Psoriatic Arthritis Diagnosis

The month of May is very personal for us at MyPsoriasisTeam, because we honor Arthritis Awareness...
Psoriasis is an autoimmune disease in which skin cells grow and build up faster than normal. Some...

Psoriasis on Feet: Symptoms, Causes, and Treatments

Psoriasis is an autoimmune disease in which skin cells grow and build up faster than normal. Some...
MyPsoriasisTeam My psoriasis Team

Two Ways to Get Started with MyPsoriasisTeam

Become a Member

Connect with others who are living with psoriasis. Get members only access to emotional support, advice, treatment insights, and more.

sign up

Become a Subscriber

Get the latest articles about psoriasis sent to your inbox.

Not now, thanks

Privacy policy
MyPsoriasisTeam My psoriasis Team

Thank you for signing up.

close