Symptoms

Symptoms of food allergy can affect many parts of your body, including your:

• Digestive system. Symptoms include stomach cramps, nausea, vomiting, diarrhea, itching in the mouth and throat, and rectal bleeding (rare in adults). These symptoms occur more often in children than in adults.
• Skin. Symptoms include hives or welts, swelling, itching, redness, and atopic dermatitis. Skin reactions are common in children.
• Respiratory system. Symptoms include coughing; wheezing; an itchy, stuffy, runny nose; sneezing; and trouble breathing.

Children usually have the same symptoms as adults. Symptoms of milk or soy allergies in children may include eczema, a runny nose, and wheezing. But sometimes the only symptoms are extreme crying (colic), vomiting, blood in the stool, diarrhea, constipation, or poor growth.

Symptoms vary from mild to life-threatening and can appear from within minutes to days of eating a food. The most severe reaction is anaphylaxis, which affects many body systems and can be deadly.

Anaphylaxis can start within a few minutes to a few hours after you eat the food. And the symptoms can go away and come back hours later. Common triggers for anaphylaxis are peanuts, nuts, and seafood. In children, peanuts cause anaphylaxis more often than other foods.^{2, 3} Aspirin, exercise, or alcohol can increase the risk for anaphylaxis.²

Symptoms may be more severe if you also have another type of allergy, such as an allergy to pollens or mold. Tobacco smoke, stress, and colds can also make symptoms worse.

There are many other conditions with similar symptoms, such as food poisoning and inflammatory bowel disease.