Food Allergies vs. Food Intolerance: What’s the Difference?


Food allergies and food intolerance are often lumped into the same category by worried parents. And, it's easy to understand why. Both conditions cause seemingly similar physical reactions following the consumption of certain foods.

But, it’s important to understand the difference between these two food-related conditions. Once you do, you can take the proper precautionary steps for your child.

Food intolerance, or food sensitivity, is a condition that causes the body to experience discomfort. It’s generally not considered dangerous, and parents can keep it under control, so long as you limit the amount of the offending food in your child’s diet. 

Food allergies, on the other hand, can be life-threatening. If a child comes into contact with even minute amounts of the offending food, the consequences may be severe.

As a parent, you should learn the differences between food intolerance and food allergy symptoms. With this understanding, you can more easily catch serious symptoms and pursue the best course of action for your kids. If you believe your child may be experiencing signs of a food allergy, visit an immunologist or allergist as soon as possible.

Food Intolerance Symptoms and Causes

As the name implies, food intolerance is the body’s inability to fully and comfortably tolerate a particular food. The two leading causes of food intolerance are:

  • The inability to fully and comfortably digest a specific type of food. Usually, it's due to deficiencies in digestive enzymes, substances that help your body digest foods. For example, lactose-intolerant individuals lack an essential enzyme called lactase. Lactase is vital to breaking down milk products in the digestive system.

  • Sensitivity to food additives or chemicals that are present in some foods. These additives include preservatives, dyes and flavorings. A typical food irritant is monosodium glutamate (MSG), a flavor enhancer added to many foods.

Food intolerance symptoms are likely to cause discomfort. But, these symptoms are rarely dangerous or life-threatening. They generally occur within a few hours of consuming an offending food. The most common food intolerance symptoms include:

  • Gastrointestinal issues such as pain, gas, diarrhea and bloating

  • Nausea

  • Skin rashes and itching

  • Irritability

  • Headaches

Food Allergy Causes and Warning Signs

Unlike food intolerance, food allergies are caused by the body’s immune reaction to particular foods. When a child develops a food allergy, their immune system recognizes certain foods as harmful. The immune system overreacts to protect itself by secreting antibodies, like Immunoglobulin E (IgE). It releases histamine, which can cause discomfort or toxic bodily shock (anaphylactic shock).

**If you suspect that your child may be experiencing food allergies, it’s important to see an immunologist or allergist immediately and create an Anaphylaxis Action Plan in case your child is ever accidentally exposed.**

Mild to moderate symptoms of food allergies can appear within minutes to an hour after eating a food allergen and may include:

  • Red, itchy hives or welts on the skin

  • Facial skin redness

  • Sneezing or nasal symptoms

  • Digestive symptoms such as nausea, diarrhea or stomach pain

  • Itchy mouth or ears

When allergic reactions are severe, your child is at risk for anaphylaxis and must receive emergency medical care immediately. Some symptoms of anaphylaxis include:

  • Swollen lips, tongue or throat

  • Wheezing or trouble breathing

  • Chest pain

  • A drop in blood pressure

  • A weak pulse or loss of consciousness

Identifying Food Reactions and Seeking Treatment

Confusing the symptoms of food intolerance and food allergies is easy to do. Both can involve the digestive system and skin rashes. 

However, food allergies are generally much more worrying and need to be correctly identified. You can learn to differentiate between the two conditions. Then, you can be proactive in identifying symptoms and seeking appropriate treatment for your child.

An allergist or immunologist can test your child for the presence of food allergies. Food intolerance is generally diagnosed through the elimination of foods as guided by your child’s doctor. Note that each allergic reaction or food intolerance symptom can differ from child to child.

To learn more about the food allergies and the difference between food allergy and intolerance, read An Overview of Food Allergies for Parents in Need of Answers and download one or more of our free toolkits.