Causes of Psoriasis

Medically Reviewed by Debra Jaliman, MD on August 12, 2022

What Causes Psoriasis?

Psoriasis turns your skin cells into overachievers: They grow about five times faster than regular skin cells. And your body can't keep up. The old cells build up instead of sloughing off, making thick, flaky, itchy patches.

Why do these cells go a little haywire? There's more going on under the surface of this skin disease.

The exact cause of psoriasis is still a mystery. Researchers think something sets off your immune system. But it's probably a combination of risk factors and triggers.

Psoriasis Risk Factors

Your genes and your immune system

Little bits of your DNA, called genes, are instructions for your cells. They control your eye and hair color, whether you can taste certain things, and the other ways your body works. Some genes are active only at certain times.

When you have psoriasis, the genes that control your immune system’s signals get mixed up. Instead of protecting your body from invaders, as it's designed to do, it promotes inflammation and turns skin cells on overdrive.

Scientists have found about 25 genes that are different in people with psoriasis. They think it takes more than one to cause the disease, and they're looking for the main ones.

About 10 in every 100 people have genes that make them more likely to get psoriasis, but only two or three of them actually do.


Heavy drinkers have a higher risk, especially younger men. Alcohol can make treatments less effective too.


Lighting up can double your risk of getting psoriasis. If you also have relatives with the condition, you're nine times more likely to get it. And smoking makes it harder to get rid of symptoms. It's closely linked with a hard-to-treat type called pustular psoriasis, which affects the palms of your hands and the soles of your feet.

Psoriasis Triggers

Hormone changes

The condition often shows up or flares during puberty. Menopause can also trigger it. During pregnancy, your symptoms may get better or even go away. But after the baby’s born, you might have a flare.


Scientists think your immune system may respond to emotional and mental pressures the same way it does to physical problems like injuries and infections.


Some treatments can make psoriasis worse. These include:

Steroid withdrawal

Topical steroids – medications that fight inflammation, in forms that you put on your skin – are some of the most common psoriasis treatments. But they can also cause symptom flares if you stop using them too quickly.


Psoriasis usually is worse in the beginning stages of HIV infection, but it gets better after you start certain treatments.

Other infections

Strep infections, in particular, are linked with guttate psoriasis, which looks like small red drops. Kids will often have strep throat before their first flare. Earaches, bronchitis, tonsillitis, or a respiratory infection such as a cold or the flu may also be triggers.


A little natural light is good for most people with psoriasis. But for a few, the sun makes their condition worse. So can a bad sunburn, so protect your skin if you’re going to be outside.

Skin injuries

A cut, scrape, bug bite, infection, or too much scratching can trigger the condition.


People who are obese tend to get plaques in their skin creases and folds.


Your psoriasis might be worse in the winter. Dry air, less natural sunlight, and cold temperatures can make symptoms worse. Keep your skin moist, and try a humidifier at home.

Show Sources


National Psoriasis Foundation: "Psoriasis Causes and Known Triggers," "Genes and Psoriasis," "Stress," "How Cigarettes and Alcohol Affect Psoriasis," "Pregnancy and Nursing," "Frequently Asked Questions: Psoriasis in spring, summer, fall and winter," "Steroids."

NHS Choices: "Psoriasis - Causes."

Medscape: "Dermatological Management of Human Immunodeficiency Virus (HIV)."

American Osteopathic College of Dermatology: "Palmoplantar Pustulosis."

Ceovic, R. BioMed Research International, 2013.

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