Food Allergic Reaction v. Eczema Flare-Up: Which One Is My Child Having?

What is the difference between a food allergic reaction and an eczema flare-up? Learn what triggers each one, what each one looks like, and how to know if your little one is experiencing a flare-up or an allergic reaction. 

Food allergies and eczema are closely related. They’re both considered “allergic conditions,” and they both involve the immune system. And babies who have eczema are at the highest risk for developing a food allergy in the future. 

If your child has an adverse reaction to a food, they could have an allergy to that food. But they could also be experiencing an eczema flare-up, because foods can cause both.

How to tell the difference between a food allergy reaction and an eczema flare-up, to make sure your child receives the right care? Read on in this guide for parents and caregivers. 

The Atopic March, Eczema, and Food Allergies

Eczema (atopic dermatitis) and food allergies are both considered allergic conditions, and both are part of the atopic march.  Babies usually develop eczema before food allergies, and babies with eczema are at the highest risk for developing a food allergy. 

What is the atopic march? The atopic march describes how children with one allergic condition are at increased risk for others, and how allergic conditions often appear in a certain order (one condition usually “marches” in front of the other, in a fairly predictable lineup).

This means that the order your baby’s symptoms appear can indicate whether your baby has eczema or food allergies. Eczema will usually appear before food allergies. 

What triggers an allergic reaction to food?

Our immune systems are designed to  protect our bodies from foreign invaders, including harmful bacteria and viruses. But when someone has a food allergy, their immune system mistakes the proteins of a certain food for foreign invaders. 

When the person eats a food that they are allergic to, their immune system tells their body to over-defend itself against the food’s proteins. This triggers an allergic reaction. 

What do food allergic reactions usually look like?

Hives and vomiting are the most common symptoms of a food allergic reaction in babies and young children. 

Here is one example of what hives caused by a food allergy reaction may look like. They will appear as red, raised bumps.

Mild or moderate food allergic reactions can also cause swelling of the face, lips, and eyes.

Usually, allergic reaction symptoms appear seconds to minutes after someone eats a food that they are allergic to, and almost always within 2 hours of eating the food. 

But people with food allergies don’t always show the same symptoms every time they have an allergic reaction. Every reaction could be different, so there’s no way to predict what an allergic reaction will look like in your child. 

Most importantly, remember that mild to moderate allergic reactions can sometimes quickly turn severe, even if your child has never had an allergic reaction before. 

What do severe food allergic reactions look like?

Symptoms of a severe food allergic reaction can include:

  • Swelling or tightness of the throat 
  • Swelling of the tongue
  • Difficulty breathing
  • Noisy breathing
  • Difficulty swallowing
  • Persistent coughing
  • Wheezing
  • Difficulty vocalizing
  • Change in cry or voice
  • Diarrhea 
  • Pale appearance 
  • Feeling floppy (only in infants and young children)
  • Dizziness 
  • Fainting/Collapsing

When a food allergic reaction causes severe symptoms and involves more than one organ system, it is classified as anaphylaxis. Anaphylaxis can be life-threatening. Call 911 and inject epinephrine (an Epi-pen) immediately if your child shows signs of anaphylaxis. 

What triggers an eczema flare-up?

If your child has eczema, it may flare up when their skin is exposed to any number of  triggers.

These are some of the triggers that may cause eczema flare-ups:

  • Dry skin
  • Dry air
  • Heat
  • Skin infections
  • Fabrics (like polyester, nylon, or wool), 
  • Fragrances (found in soaps, laundry detergents, lotions, and shampoo)
  • Dyes (also in soaps, detergents and shampoo
  • Chemicals
  • Metals
  • Common allergy-causing foods or environmental allergens could also trigger a flare-up, especially if your child already has one of these allergies.

Eczema Flare-Ups: What do they look like?

Eczema makes someone’s skin dry, itchy, and red. It can cause patches of red or dry skin, itchy and rough skin, or crusty bumps and scales that sometimes leak fluid.

When these symptoms suddenly appear or get worse, this is known as a flare-up.

Eczema flare-ups will usually appear on the cheeks, scalp, forehead, elbows, knees, arm joints or leg joints, but they could appear anywhere on the skin. 

Food allergic reaction VS. Eczema flare-up: How to tell the difference?

Foods can trigger both allergic reactions and eczema flare-ups. So, how can you tell the difference?

If someone has both eczema and food allergies and eczema, their eczema may get worse when they have a food allergy reaction.

But food allergy reactions can potentially cause many symptoms that eczema can’t cause (like swelling and vomiting).  

And even though hives and eczema rash may seem similar, the itchy red rash associated with eczema is actually very different from the raised bumpy hives that food allergies can cause.

The baby shown above has eczema, and it has caused a red, itchy rash.

Food Allergic Reactions Are Consistent

If your child has a food allergy, they’ll develop an allergic reaction shortly after eating a “problem” food, every time they eat it (although symptoms could differ each time). If you completely remove the food(s) they are allergic to from their diet, they will no longer show symptoms of a reaction. 

As the National Eczema Association explains it, food allergic reactions are “reliable, reproducible, consistent and timely.” 

  • Reliable and consistent: The reaction occurs every time someone eats the food
  • Reproducible: If someone would eat the food again, they’d have another allergic reaction
  • Timely: The reaction occurs within seconds to hours

So, what if your child has eczema and they flare up in response to a food?

Consider the timing. Whenever your child appears to have a flare-up, keep a record of all their surroundings.  For example:

  • Did you use soap, shampoo, or lotion with a fragrance? 
  • Did they just sleep with a wool blanket against their skin?
  •  Are they wearing polyester, nylon, or wool?

In addition, keep track of everything they ate within the past 2 hours.

 It can be difficult, but finding and removing other consistent eczema triggers can help you figure out whether food is an eczema trigger—or an allergen.

Also, remember that allergic reactions are consistent. If your child sometimes gets flare-ups when they eat a certain food, and sometimes eats that food with no issues, they probably don’t have an allergy to that food.

If they don’t show other symptoms of an allergic reaction when they eat a certain food, you can probably rest assured that they don’t have an allergy to that food.

Still, allergy testing is the most reliable way to determine whether your child has a food allergy. And food challenges are the only form of testing that can definitively diagnose a food allergy.

Can babies “outgrow” food allergies? Can they “outgrow” eczema?

Most food allergic reactions like hives should go away within a few days or weeks after you identify and remove the “problem” food (or foods) from baby’s diet. As long as you successfully keep the “problem” food(s) out of baby’s diet, baby shouldn’t experience any more food allergy reactions.

 And sometimes, babies “outgrow” their food allergies when they’re older, meaning they become able to eat the food they were once allergic to without a food allergy reaction. Some food allergies are lifelong, though, so your child may have to avoid their “problem” foods for the rest of their life to prevent an allergic reaction. And besides “outgrowing” the food allergy, which is unpredictable, there is no cure for food allergies.  

Eczema usually starts in infancy, and can range from mild to severe. Chronic eczema is the most common type of eczema and can be lifelong.Triggers of eczema flare-ups can often be difficult to identify, so it may be harder to remove the triggers.  And just like food allergies,  there is no cure for eczema. 

Reducing Eczema Babies’ Food Allergy Risk

If your baby is less than a year old, and does not show signs of peanut allergies, ask your doctor about introducing them to peanut early and often. After all, new dietary guidelines from the USDA recommend this approach to introducing peanut especially for babies with eczema, as it may help prevent food allergies.

According to the USDA’s new Dietary Guidelines,  “if an infant has severe eczema…age-appropriate, peanut containing foods should be introduced into the diet as early as age 4 to 6 months. This will reduce the risk of developing peanut allergy.”

Feeding your baby peanut consistently, starting as early as 4 months of age, can help reduce your baby’s food allergy risk. This introduction is especially important for babies with eczema, because of their increased food allergy risk. And as other international medical guidelines state, early introduction of other foods may be beneficial for food allergy prevention in eczema babies as well.

Your doctor may recommend allergy testing before you start, though, especially if your baby’s eczema is severe.

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