Food Allergy Facts

Is It an Intolerance or Allergy?

My child is gassy and fussy after eating a certain food. Is it an allergy?

Maybe -- but likely not. Food allergies are often blamed for a whole group of symptoms that aren't really consistent with allergies, according to Todd Green, MD, a pediatric allergist and immunologist at Children's Hospital of Pittsburgh. Gassiness and cranky behavior are among the symptoms that could have other causes, including an intolerance to a food, such as milk (see the comparison chart below). "Most perceived food allergies aren't demonstrated to be actual allergies when kids are tested," Dr. Green says. Even seemingly obvious symptoms like a rash or vomiting could be due to something else. "Kids get hives with viral infections, and they throw up with gastroenteritis," he adds.

Milk Allergy or Intolerance?

After drinking a bottle of cow's milk-based formula or a glass of milk, your child vomits and has diarrhea. Must be a milk allergy, right? Don't be so sure. Gastrointestinal upset can be a symptom of an allergy or the sign of a milk intolerance. Here's a breakdown of what separates these two conditions.

Cause
Milk Intolerance: Baby can't digest the sugar lactose found in milk
Milk Allergy: The immune system mistakes the protein in milk for a harmful microbe

Symptoms
Milk Intolerance: Diarrhea and/or vomiting; gassiness
Milk Allergy: Stomach problems and/or hives, swelling of lips and eyes, wheezing, and anaphylactic shock

How Much Is Needed for a Reaction
Milk Intolerance: A fair amount
Milk Allergy: A tiny amount

Typical Treatment
Milk Intolerance: A lactose-free formula; baby may be able to drink lactose-free milk and eat yogurt, cheese, or ice cream
Milk Allergy: A hypoallergenic formula in which the milk proteins have been broken down enough to avoid causing a reaction; avoid milk and dairy foods