When you have eczema, everything from dust to dairy foods could lead to dry, itchy skin. That's because allergies and eczema are closely connected.

Up to 80% of children with eczema also have asthma or allergies to pollen, dust mites, pet dander, mold, or certain foods. Doctors call these three conditions -- eczema, allergies, and asthma -- the atopic triad because they so often occur together.

What's Behind the Link?

Scientists are still on the hunt for the connection between eczema and allergies. The question is, which comes first? Do allergies cause eczema? Does eczema cause allergies? Or do the two just happen together?

Genes do seem to play a role. Kids who have a parent, brother, sister, or other family members with allergies or asthma are more likely to get eczema.

People with both eczema and allergies have a change to a gene called filaggrin. It’s a protein that keeps the skin moist. People who don't make enough of this protein lose more water from their skin, which causes the dryness and itchiness of eczema. The lack of filaggrin also makes the skin let in more allergens like dust and pollen.

One study found that infants with eczema had a breakdown in their skin barrier that made them more likely to get food allergies. That breakdown exposed immune cells in their skin to proteins in foods like eggs and cow's milk. These proteins caused their immune system to react.

Food Allergies and Eczema

If you have eczema, eating -- or just touching -- certain foods can make your skin flare up. This is most common with young children.  Kids younger than 5 who have eczema should get tested for allergies to foods like eggs, milk, peanuts, wheat, and soy. No matter what your age, you should see an allergist if you have a reaction to foods.

Food allergies linked to eczema include:

  • Cow's milk and other dairy products
  • Eggs
  • Nuts
  • Soy
  • Wheat

How can you tell which foods cause flare-ups? Sometimes the best way is to look for skin symptoms after you eat that food. Your doctor can also give you a test called a food challenge. You eat the food that you think may cause the symptoms, then your doctor watches for a reaction.

Other Allergies and Eczema

Many other things that cause allergies also can cause eczema flare-ups, including:

  • Dust mites
  • Makeup and other cosmetics
  • Mold
  • Pet dander
  • Pollen
  • Soaps

Try to avoid the things that set off your skin symptoms. The search for what you're allergic to can take some trial and error. One way to know if you have an allergy is to see if your skin flares up when you're exposed to something.

Your doctor can also test you for allergies by putting a little bit of a substance on or under your skin. If you're allergic, a red bump will pop up. Your doctor may also do a blood test to check for something called IgE. Your body makes that when you come in contact with something you’re allergic to.

How to Cut Down Eczema Flares Caused by Allergies

One way to curb eczema flares is to learn what sets off your allergies and then avoid them. Here’s how:

  • Use only gentle, scent-free soaps, lotions, detergents, and cosmetics.
  • Stay indoors when pollen counts are high.
  • Keep your windows closed and the air conditioning on to keep pollen out of your house.
  • Wash your sheets and pillowcases in hot water every week to kill dust mites.
  • Place dust-mite-proof covers on your mattresses.
  • Keep the humidity in your house set at below 45% to prevent mold growth.
  • Use an exhaust fan while you shower or take a bath to stop mold from growing on your bathroom walls.

You can also ask your doctor about allergy shots. These slowly expose your body to more and more of something that triggers your allergies. Over time, these shots can stop allergy symptoms. They can also help some people with their eczema.

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