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If your child has itchy eczema, could diet be to blame? It's possible. Up to one out of three kids with eczema has a food allergy that could be making symptoms worse. Avoiding some foods could make a big difference.

But since finding food triggers is tricky -- and eczema can have lots of other causes -- don't jump to conclusions. Be methodical, and work closely with an allergist.

What Foods May Trigger Eczema?

When you have a food allergy, your body reacts to a harmless food as if it's a dangerous germ and attacks. Allergy symptoms, like swelling, are side effects of your body's defenses.

Food allergies can make eczema worse in some kids. Babies and young children are more likely to have food triggers for eczema than older kids.

Some foods are more likely to trigger symptoms than others. These foods cause 90% of all food allergies:

  • Milk
  • Eggs
  • Peanuts
  • Tree nuts
  • Wheat
  • Fish
  • Shellfish
  • Soy

While trigger foods can make eczema worse, experts don't think foods are really the original cause of the eczema. Instead, eczema seems to result from a "leakiness" in the outer layer of skin that allows in irritants, germs, and allergens.

How to Find a Food Trigger

Some food allergies are obvious. If your child eats lobster for the first time and breaks out in hives 15 minutes later, the link might be clear.

But with food triggers and eczema, it's often not so obvious. The symptoms may not show up for days after eating a food. While stopping a trigger food may help, it may not make the eczema disappear. And remember that most kids with eczema don't have a food allergy at all.

That's why working with a doctor is so important. He or she can guide you toward the real cause. Your child's doctor might recommend tests like:

Elimination diets. If a doctor suspects a food, he or she may recommend cutting it out for 10 to 14 days. Watch to see if it makes a difference.

Food challenges. After you've taken a food out of your child's diet, your pediatrician might want you to add a small amount back in to see if it causes symptoms. Your doctor may want to do a food challenge in the office, in case your child has a reaction.

Skin testing. A doctor can take an extract of the food and use it to scratch the skin lightly. If the area swells up, it's a sign of an allergic reaction. However, sometimes it's not accurate.

Blood tests. RAST -- radioallergosorbent test -- can check for special cells in the blood that are signs of specific food allergies. Generally it’s less accurate than skin tests. Other lab tests can check for cells that trigger swelling.

Tracking down a food trigger can take patience and detective work.

Be methodical. Eliminate only one food at a time. If you ban dairy and gluten at the same time and symptoms get better, you'll have no idea which one made the difference. Use a food diary to record foods and symptoms.

Move slowly. Accommodating a food allergy isn't easy. And eliminating too many foods could also cut out important nutrients your child needs to grow and develop. So for your child's sake and yours, be certain before eliminating a food from your child's diet permanently. Work with your doctor. Remember that a positive skin test isn't reason enough to cut out a food -- lots of kids test positive for foods that don't really cause symptoms.

Keep using other treatments. Even if your child does have an eczema trigger food, cutting it out may not make the rash disappear. So continue the other treatments your doctor recommends -- like skin ointments, lotions, medications, and avoiding other allergens like dust mites, pollen, or pet dander.

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