Food Allergy 101: Is It A Food Allergy, Or Something Else?

May is Food Allergy Awareness Month. Food allergies affect over 30 million Americans, including 1 in 12 children. Anyone can develop a food allergy at any time. And when someone with a food allergy eats even a small amount of the food they’re allergic to, their body will develop an allergic reaction that could potentially be severe or even life-threatening. 

We’re dedicating the month of May to answering common food allergy questions, as well as helping families and communities take action surrounding food allergies.

Today, we’re sharing how to tell whether your child is experiencing a food allergy reaction, or something else that only seems similar.

Is your child experiencing a food allergy reaction, or something else? A rash, vomiting, or stomach pain could be signs of a food allergy. But there are other reasons that food could cause GI symptoms, and other conditions that cause rashes. 

How to tell the difference? Although you’ll need allergy testing to know for sure, we’re here to help you narrow down what might be causing their symptoms.

What causes a food allergy reaction?

Normally, our immune systems protect us from harmful viruses and bacteria. But when someone has a food allergy, their immune system treats the food(s) they’re allergic to – called their allergen(s) – like one of these harmful invaders. Their immune system makes antibodies called IgE antibodies, which detect and help fight off the proteins from these foods. 

Every time someone with a food allergy eats even a small amount of their allergen, their immune system overreacts and triggers the symptoms of a food allergic reaction. These reactions can range from mild to severe – and any food allergy reaction could become life-threatening. 

The symptoms may vary from reaction to reaction, so you can’t predict what symptoms someone will have based on previous reactions.

Symptoms of a food allergy reaction usually develop seconds to minutes after someone eats a food they are allergic to, and almost always develop within two hours. 

What are the most common food allergy symptoms?

In babies and young children, hives and vomiting are the two most common symptoms of an allergic reaction. 

Food allergy hives are raised, itchy bumps that are usually rounded. They usually appear in clusters, and can last for up to 24-48 hours. 

  • On children with darker skin, hives are usually the same color as the skin, although they can sometimes be dark red.
  • On children with lighter skin, hives are red and usually have a red flare around them.

What are the mild and moderate symptoms of a food allergy reaction?

Mild to moderate symptoms of a food allergy reaction include:

  • Hives in just one area of the body
  • Occasional vomiting
  • Itchiness
  • Skin redness in one area
  • Swelling of the eyes, lips, or face
  • Itchy, watery eyes
  • Congestion
  • Sneezing
  • Mild coughing
  • Some stomach pain
  • Some nausea

What are the severe symptoms of a food allergy reaction?

When the symptoms of a food allergy reaction are severe and involve more than one organ system, this is known as anaphylaxis. Anaphylaxis can be life-threatening. Call 911, and give epinephrine (use an Epi-Pen) immediately, if your child shows signs of anaphylaxis. 


Severe food allergy symptoms include: 

  • Hives that cover many areas of the body
  • Swelling of the tongue
  • Swelling or tightness of the throat
  • Trouble breathing 
  • Trouble swallowing
  • Shortness of breath
  • Repeated, significant coughing
  • Noisy breathing (wheezing)
  • Pale appearance
  • Trouble vocalizing
  • Change in voice or cry
  • Repeated vomiting
  • Diarrhea 
  • Dizziness
  • Fainting
  • Drop in blood pressure
  • Rapid heartbeat
  • Loss of consciousness
  • Feeling floppy (only in infants and young children) 

Does my child have a food allergy, or something else?

It’s important to know the difference between food allergies and similar conditions, so your child can get the proper care.

Remember: To definitively diagnose a food allergy, your child will need to undergo food allergy testing – skin prick testing, blood testing, and/or an oral food challenge.


Triggered by food?

Looks like hives or rash?

With GI symptoms?

With fever?

With congestion?

Food allergy 

Yes

Yes, commonly

Sometimes

No

Sometimes

Food intolerance

Yes

No

Yes

No

No

Celiac disease

Yes

No

Yes

No

No

Eczema

Sometimes

Yes

No

No

No

Hives from other sources

No

Yes

Sometimes

No

Sometimes

Viral rashes

No

Yes

Not usually

Yes

Sometimes

Baby acne 

No

Yes

No

No

No

Heat rash

No

Yes

No

No

No


Here are some conditions and illnesses that may seem similar to food allergies, but that are very different.

Food intolerances (food sensitivities)

Food intolerances (food sensitivities) are often confused with food allergies, but the two are very different. 

Food intolerances also cause symptoms after someone eats a certain food. But while food allergies always involve the immune system, food intolerances never involve the immune system.

Rather, most food intolerances involve the digestive system, and happen because someone can’t properly digest a food. 

  • The most common food intolerance is lactose intolerance, which happens when someone’s body doesn’t make enough lactase enzymes to digest the sugars in milk. 
  • Another common intolerance is gluten intolerance, which causes digestive symptoms when someone consumes gluten (a protein found in wheat and other grains).

The American Academy of Allergy, Asthma, and Immunology provides more details on allergies vs. intolerances:  

 

 Since they’re digestive-based, food intolerances often cause symptoms such as diarrhea, bloating, gas, stomachache, nausea, vomiting, and abdominal pain. 

How to know whether your child has a food allergy or food intolerance?

  • Food intolerances usually only involve GI symptoms, and don’t cause hives like allergies do.
  • Many people with food intolerances can eat small amounts of their problem food with no issue, but people with food allergies have allergic reactions after eating even tiny amounts of food. 
  • Food intolerances can’t cause life-threatening anaphylaxis like food allergies can.
  • And while food allergy symptoms take seconds to a few hours to appear, food intolerance symptoms appear hours to a few days after someone eats one of their “problem” foods. 

Note: There are rare types of food allergies that mostly cause digestive symptoms, but that count as allergies because they involve the immune system. Symptoms of these rare allergies also appear hours to days after someone consumes a food, like food intolerances do. However, these “delayed-type” food allergies are much rarer than food intolerances. Learn more about delayed-type food allergies here. 

 

Celiac disease

Celiac disease is an autoimmune disorder that makes the body react to gluten, a protein found in wheat, barley, rye, and triticale. When someone with celiac disease eats foods containing gluten, their body can’t properly process the food, and this triggers an immune response. 

Celiac disease does involve the immune system, so it’s different from traditional food intolerances. But it’s also not considered a food allergy – there’s no such thing as an allergy to gluten. After all, celiac disease can’t cause life-threatening anaphylaxis, and the proteins that cause the response aren’t unique to one food (they can be found in several different types of grains). 

Still, celiac disease can be very serious. Since the body can’t process nutrients properly when celiac disease is involved, this may hinder a child’s growth.

The immune response of celiac disease leads to inflammation in the small intestine, which could last into the long term. It also causes GI symptoms, like diarrhea, stomach pain, constipation, bloating, and vomiting.

Unlike traditional food intolerances, celiac disease can be diagnosed with a blood test, as well as with a test where a camera is used to check the small intestine. 

Eczema

Eczema is also called atopic dermatitis. It is a skin condition that flares up (produces a rash) when the skin is exposed to a trigger – an irritant or existing allergen. 

Most commonly, eczema rash is dry, flaky, rough, and very itchy, and appears on the face, scalp, elbows, knees, and joints. But it could appear anywhere on the body.

It can cause inflamed dry skin, rough and itchy skin patches, or scaly and crusty bumps that can sometimes leak fluid.

Eczema is flat, not raised like food allergy hives. And it only causes skin symptoms, not swelling, vomiting, or any of the other symptoms associated with an allergic reaction.

On children with lighter skin, eczema rash will be red.

Close up Asian Newborn baby boy with Common skin rash on his face and ear (stock photo)


Atopic dermatitis newborn feet eczema (stock photo)


And on children with darker skin, eczema rash is usually brown, purple, or gray. It may be hard to see the rash, but you’ll be able to detect the dry skin. (See here for several images of what baby eczema looks like on darker skin.)

Some common eczema triggers are dry skin, dry air, fragrances, dyes, chemicals, certain fabrics, and environmental allergens. Food can also be an eczema trigger. 

How to know if food is an eczema trigger or an allergen?

  • Keep track of the possible eczema triggers your child was exposed to, then try to remove them. 
  • Also, keep track of what your child ate in the last 2 hours, and whether you see other symptoms.

If your child always reacts within 2 hours of eating a food, they have other food allergy symptoms, and all other eczema triggers are removed, your child likely has an allergy to the food. 

But if they don't show other symptoms of an allergic reaction, and don't consistently flare up when they eat a certain food, they probably aren’t allergic to the food. 

Hives from other sources

Not all hives are caused by food allergies. Pet allergies, insect bite or sting allergies, pollen allergies, and medicine allergies can also cause hives. 

Sometimes, irritants like chemicals, infections, or harsh materials rubbing on the skin can also cause hives. 

Like with food allergies’ hives, other hives also appear soon after a child is exposed to an allergen or irritant. All hives look the same – raised bumps, often in clusters. 

Remember that food allergy hives appear within 2 hours of eating a problem food. If your child hasn’t eaten anything in the last 2 hours but develops hives, they probably have another type of allergy if they were exposed to something else (like a dog or cat, or an insect’s sting). But food allergies are still the most common cause of hives in children. 

Viral rashes

There are several different kinds of viral rashes, all caused by different types of viruses. While the viral rash of each illness looks different, they all appear shortly after a fever. And fever is never a food allergy symptom.

Some types of common viral rashes include:

Roseola or sixth disease: After a fever, it causes a dotted, raised rash that doesn’t itch. This rash starts on the stomach, then spreads to other body parts.

Fifth disease: After a fever, it causes a flushed rash on the cheeks, and then a lacey, flat, and sometimes itchy rash that may spread to the trunk, arms, and legs. 

Hand, foot, and mouth disease: After a fever, it causes mouth sores and a blistery rash on the palms of hands and soles of feet. The rash might also appear on the buttocks, elbows, and/or knees. 

To learn more about these and other kinds of viral rashes, visit our viral rash guide here. 

Baby acne

We don’t know the reason behind baby acne, but many babies develop it between 2 and 6 weeks of age, and that’s perfectly normal. Baby acne appears as hard, raised bumps, which look like the acne that teens and young adults develop. It usually appears on the face, back, neck, and chest.

Baby acne could appear any time between 2 and 6 weeks of age. It lasts much longer than the hives from food allergies last – for days to months rather than hours.

Heat rashes

Heat rashes look similar to baby acne, but suddenly appear on a very hot day. These rashes usually don’t appear alongside any other symptoms, and tend to appear on the areas of the body that are most prone to heat (the face, wrists, armpits, other parts of the arms, and legs). You’ll usually be able to tell that heat – not, say, food or a fever – caused the rash. 

Takeaways for parents: Food allergy or different condition?

If your child has symptoms similar to the ones described above, and you aren’t sure if they have a food allergy, keep track of what symptoms emerged and how long ago your child ate. 

Even though a test is required to definitively diagnose a food allergy, remember that food allergies:

  • Cause symptoms seconds to hours after eating a food
  • Can have a wide range of symptoms, but hives (raised, round bumps) are most common
  • Can cause GI symptoms, which can be accompanied by symptoms outside the GI tract
  • Can cause different symptoms with every reaction
  • Never involve a fever

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