If you have psoriasis, you may be concerned about it spreading, either to other people or on other parts of your own body. Psoriasis isn’t contagious and you can’t catch it from someone else or pass it on to another person. However, psoriasis can spread to other parts of your own body if you already have it.

Read on to learn how psoriasis develops and ways to prevent it from getting worse or spreading.

Psoriasis is a very common, chronic skin condition. It’s caused by your immune system working on overdrive, which increases your production of skin cells. As the production increases, your skin cells die and regrow more quickly. That causes a buildup of dead skin cells that results in itchy patches on your skin. The patches can be red, very dry, and very thick.

Psoriasis has two main risk factors: your immune system and your genetics. These two factors affect your whole body, so you can develop psoriasis in many places. Psoriasis is most common on the scalp, knees, and elbows, but it can appear anywhere.

Psoriasis can also range from mild to severe. In mild cases, psoriasis patches cover less than 3 percent of your body, and in severe cases the patches cover more than 10 percent. It’s possible for your psoriasis to become more or less severe over time. Psoriasis can also look and feel different depending on its location.

It may seem as though your psoriasis is spreading to other parts of your body if it becomes more severe. But in actuality, you’re having what’s called a flare-up.

Researchers believe that more people have the genes for psoriasis than those who actually develop it. It’s thought that a combination of genetic and environmental triggers must be present for psoriasis to occur. That’s also likely an explanation for why psoriasis comes and goes, or gets better and worse over time.

Psoriasis flare-ups can be triggered by various factors, including:

  • an infection anywhere in your body
  • smoking
  • skin injury, like a cut or burn
  • stress
  • dry air, either from the weather or from being in a heated room
  • too much alcohol
  • some medications
  • vitamin D deficiency
  • obesity

Treatment is focused on preventing you from producing skin cells too quickly, but there are also steps you can take to help prevent psoriasis flare-ups.

Read more: 10 psoriasis triggers to avoid »

1. A healthy diet

Eating a healthy diet is important for everyone, but may also help reduce psoriasis flare-ups.

In a recent survey in the United States, people with psoriasis reported an improvement in their symptoms after reducing their alcohol, gluten, and nightshades intake. Nightshades include potatoes, tomatoes, and eggplants, among other things. Improvement was also seen in those who added omega-3s and fish oil, vegetables, and vitamin D supplements to their diet.

There have been few scientific studies on the effects of diet on psoriasis, however. Talk to your doctor about an ideal diet for you.

2. Avoid smoking and alcohol

This one may be easier said than done. Smoking and alcohol do little to aid in a healthy lifestyle, and they may aggravate psoriasis. Limit your consumption of smoking and alcohol as much as possible to prevent psoriasis from getting worse. Talk to your doctor if you need help quitting. They can recommend smoking cessation programs and resources to help manage alcohol intake.

Read more: 15 tips for quitting smoking »

3. Protect your skin

Sunburn, cuts, and even vaccinations can trigger psoriasis. This kind of trauma to the skin can cause a response called the Koebner phenomenon. It can cause psoriasis patches to develop in areas where you don’t normally experience flare-ups, which can also make it seem like the psoriasis has spread. To avoid this from happening, try these tips:

  • Use sunscreen if you’ll be in the sun for extended periods of time. While some ultraviolet light may help heal your psoriasis, too much exposure can damage your skin, and may even lead to skin cancer.
  • Take extra care to avoid cuts or scrapes.
  • Keep a close eye on your skin following vaccinations. Vaccinations could lead to a psoriasis flare-up.

4. Decrease stress

It’s not always easy to manage stress, and it can be unavoidable at times. Anything from a sudden life change, like a job transition or the loss of a loved one, to the chronic stress of everyday life is linked to an increase of psoriasis.

Here are some things you can do to try to reduce your stress:

  • Keep your schedule manageable.
  • Find time to do the activities you enjoy.
  • Spend time with people who uplift you.
  • Keep your body healthy.
  • Take a few moments each day just to breath and clear your mind.

Learn more about stress management »

5. Sleep

Getting enough sleep can support your immune system and may help you maintain a healthy body weight and manage stress. All of these things are important for keeping your psoriasis at bay.

Adults are recommended to get seven to eight hours of sleep per day. See your doctor if you have any trouble with getting enough sleep.

Learn more: How does seven to eight hours of sleep affect your body? »

6. Reconsider some medications

The following medications are associated with psoriasis flares:

Talk with your doctor if you think one of these medications might be affecting your psoriasis. And always talk to your doctor before quitting or changing any of your medications.

7. Lotion

Overly dry skin can trigger psoriasis. Avoid overly hot showers, which may dry your skin. After bathing, pat your skin dry with a towel and apply an unscented lotion to help lock in moisture. You may also want to use a humidifier in your home if the air is dry. That can also help prevent dry skin.

Psoriasis isn’t contagious, meaning you can’t spread it to other people. Flare-ups can cause your psoriasis to get worse and cover larger amounts of your body. Learn your triggers and avoid them, when possible, to help reduce your risk for flare-ups.