Food Allergy, Intolerance, or Sensitivity?

Food allergy, food intolerance, and food sensitivity may have similarities in symptoms, but what the internal body does is different. Food Allergy, food intolerance, and food sensitivity may have similar symptoms, but what happens inside the body with each of these problems differs.

Before explaining the differences, allow me to describe our learning experiences with Baby J.

Experience #1: Our food allergy scare!

Baby J was blood tested for food allergies at 6 months old. The results came back mild, nothing was off the charts. When Baby J turned one, his then-pediatrician gave us the okay to try milk.

At 13 months old, Baby J took two sips of milk and within minutes he started to wheeze! We had a steroid-based inhaler prescribed by his allergist for wheezing, which we gave to him right away. We were scared, so we rushed to the ER. As we arrived at the hospital, his wheezing subsided, but we sat in the parking lot for about an hour to make sure nothing else would happen. When we arrived home, Baby J threw up. Not only did he throw up, but the vomit that touched his body turned his skin bright red. Hubby described it as Freddy Krueger skin. We quickly bathed off all the vomit and his skin slowly calmed down. After getting Baby J out of the bathtub, we gave him some Benadryl. Thankfully, Baby J was fine after that; no other symptoms cropped up and nothing else happened.

Reflecting back, we should have injected an epinephrine, as his multiple symptoms qualified as anaphylactic. However, we were not prescribed one yet and did not understand the severity of his reactions.

What happened?

At Baby J's 6 months blood allergy test, he was only mildly allergic to dairy. None of the doctors on his care team told us to be cautious about introducing foods. However, by 13 months, Baby J had received 5 rounds of antibiotics. He had gone through 2 rounds of antibiotics by 6 months. The more rounds of antibiotics given during infancy, the higher the risk of food allergies [1, 2, 3, 4]. For Baby J, the 5 rounds of antibiotics turned his mild dairy allergy into a severe anaphylactic allergy to dairy.

On Baby J's 15-month doctor's appointment, we asked for a prescription of  epinephrine pens. Thankfully, we have not needed to administer any.

The good news is Baby J's blood allergy test at 3 years old showed his dairy allergy IgE has decreased to the mild/moderate level. We hope that one day he will be able to consume dairy. We have yet to test dairy and won't until he is cleared or under doctor's supervision. Interestingly, Baby J's body tolerates ghee ever since he started eating solids. Ghee is clarified butter, where the milk solids (caseins) have been boiled down and removed.

Experience #2: A huge flare after 3 years of being free of topical steroids!

Baby J had a huge flare after a year of smooth and clear cheeks and more than 3 years of being free of topical steroids.

There is always something new to learn in my motherhood journey. I’m always learning something new in this journey they call motherhood.

What happened?

Baby J has a sensitivity to soy. Yup, a sensitivity -- not an allergy or an intolerance -- but a food sensitivity. Let me explain...

According to two blood allergy testings in infancy and at 1.5 years old, Baby J was mildly allergic to soy. His skin prick and blood allergy testing at 3 years old showed he was no longer allergic to soy. Per the allergist's recommendation, we excitedly and slowly introduced soy into his diet.

The reintroduction started with soy milk, then tofu. We gradually increased the amounts and months went by with no reactions!

Unfortunately, there was a month where Baby J was drinking soy milk twice a day, everyday, and sometimes had tofu on top of that. He complained a few times about his tummy hurting. None of this clicked for me, until one evening after a shower, parts of Baby J's skin were red and oozy. The following morning, he woke up with cheeks that were bright red and rough. I am talking patches of oozy redness on one calf and behind the back of one knee. This kind of flare was not sudden, but rather a gradual increase in redness, wetness, and itch that did not strike me, until it was glaring back at me. I thought we grew beyond this stage, but I was wrong.

During this time, Baby J's diet had been consistent. His nutrient-dense diet had not changed, except for the gradual increase in soy products. Baby J did not have any allergic reactions to soy, such as hives, wheezing, or swelling of body parts. Baby J's body did not have trouble breaking down his food because he was going to the bathroom on a daily basis, so I wouldn't consider soy to be a food intolerance. He mentioned his tummy hurting a few times after drinking soy milk. His belly was bloated. He was gassy. He was moody! A few rashes appeared on parts of his body that had never had eczema. All these symptoms led me to believe it was a food sensitivity to soy.

I immediately took Baby J off all soy products. Two days later, his cheeks were smooth and clear again. A few spots of eczema were no longer red and oozy, and those patches were drying up and shedding for clear skin to grow back again.

It was frustrating. After 3 years of being free of topical steroids, flares can still happen.

Baby J can still consume soy products, just in moderation.

What is a food allergy?

A food allergy is when the body's immune system overreacts to a typically harmless food (the allergen). When the immune system mistakens a substance as harmful, it triggers the cells to release an antibody called immunoglobulin E (IgE) to attack the allergen. This attack releases chemicals, such as histamine, into the bloodstream, causing allergy symptoms.

This serious and potentially life-threatening medical condition affects 1 in 13 children in the United States [5]. A food allergy reaction can happen from just a tiny trace of the allergen. Therefore, a food allergy needs to be taken seriously because it can lead to death [6].

The symptoms.

Food allergy symptoms are unpredictable and can vary from mild to severe. Allergic reactions can happen within minutes after eating the allergen, or hours later. It is important to know that a mild food allergy can progress to a severe allergy reaction, or anaphylaxis.

Mild food allergy symptoms may involve:

  • a few hives or a little itch
  • sneezing, itchy or runny nose
  • mild swelling or itching of lips/mouth area
  • minor nausea or stomach discomfort

Severe food allergy symptoms may involve any of the mild symptoms listed above, plus:

  • tightness in throat, trouble breathing or swallowing
  • wheezing, difficulty breathing, or coughing
  • full body hives, rash, or redness
  • low blood pressure leading to pale skin, weak pulse, dizziness, or loss of consciousness
  • gastrointestinal symptoms, such as vomiting, diarrhea, or cramping


Please seek a qualified medical professional for suspected food allergy evaluation, diagnosis and treatment. Skin pricks and blood tests both detect food-specific IgE. Skin prick testing results happen within 15 minutes. Blood test results take at least several days to arrive. Unlike the skin prick test, the blood test is not affected by antihistamines and can be performed for people with extensive rashes who are unable to use skin tests [7].

Top 14 allergens.

The top 8 most common food allergens are milk, peanut, tree nuts, egg, soy, wheat, fish and shellfish. The top 14 most common food allergens include the top 8, plus sesame, mustard, celery, mollusks, sulphites [8], & lupins (a legume).

What is a food intolerance?

While a food allergy is a reaction by the immune system, a food intolerance does not involve the immune system, so it is never life-threatening. A food intolerance is the body's inability to digest certain foods. Symptoms often occur a few hours after eating the suspected food.

The symptoms.

Food intolerance symptoms may involve:

  • abdominal pain or discomfort
  • intestinal gas and/or bloating
  • diarrhea
  • skin rashes and itching


Self monitoring what you eat and your symptoms is the best way to see whether you have a food intolerance. An elimination diet with a food journal is the best way to note a food intolerance. Cut out one suspected food at a time from your diet for at least 2 weeks to see if your food intolerance symptoms improve. Then, reintroduce the food to see if symptoms return. You may find you can tolerate a certain level of the suspected food and only get symptoms if you have more than a particular amount.

Common food intolerances.

Dairy is a food intolerance, or more commonly, a lactose intolerance. Lactose is the natural sugar found in milk, yogurt and soft cheeses that the body cannot digest. Another common food intolerance is wheat, or gluten intolerance. Some people have a hard time digesting wheat. Foods that usually contain wheat are bread, pasta, cereals, couscous, cakes and pastries, biscuits, doughnuts, beer, and soy sauce. Other common food intolerances are caffeine, salicylates, amines, sulfites, fructose, aspartame, eggs, monosodium glutamate (also known as MSG), food colorings, yeast, and sugar alcohol [9].

What is a food sensitivity?

A food sensitivity "is a nonspecific term that can include any symptom perceived to be related to food and thus may be subject to a wide range of usage and interpretation [10]." A food sensitivity is experiencing symptoms that are not related to food allergy, food intolerance, or celiac disease (a serious autoimmune disease where eating gluten leads to damage in the small intestine).

The symptoms.

Food sensitivity symptoms can be similar to food allergy and food intolerance, but never life-threatening. Symptoms can be delayed for a few days after ingesting the trigger food. Common food sensitivity symptoms may involve:

  • abdominal pain
  • diarrhea
  • rashes
  • joint pain
  • fatigue
  • migraines


A food sensitivity is not an official medical diagnosis. Similar to food intolerance, the best way to see if there is a food sensitivity is with a food journal and elimination diet. There are food sensitivity tests that look for immunoglobulin G (IgG) levels, not the IgE levels for food allergies. However, there is not enough evidence to support the use of IgG testing for food sensitivities.

Common food sensitivities.

Anything kind of food that is common in food allergy and food intolerance. Any food really.

An infographic summary.

Please seek a qualified medical professional for suspected food allergy, food intolerance, or food sensitivity.