Symptoms of an Allergic Reaction to Food

Learn about the mild and severe symptoms of a food allergy reaction—and what to do next.

Every three minutes, a food allergy reaction sends someone to the emergency room in the U.S.

Symptoms typically appear within minutes to several hours after eating the food to which you are allergic. An allergic reaction to food can affect the skin, the gastrointestinal tract, the respiratory tract and, in the most serious cases, the cardiovascular system.

Reactions can range from mild to severe, including the potentially life-threatening condition anaphylaxis.

Remember that reactions can be unpredictable. The first signs of a reaction can be mild, but symptoms can worsen quickly. And what caused a mild reaction one time can lead to a severe reaction the next time.

Keep in mind that children may communicate their symptoms differently than adults. Learn more about how a child might describe a reaction.

Mild to moderate symptoms may include one or more of the following

  • Hives (reddish, swollen, itchy areas on the skin)
  • Eczema flare (a persistent dry, itchy rash)
  • Redness of the skin, particularly around the mouth or eyes
  • Itchy mouth or ear canal
  • Nausea or vomiting
  • Diarrhea
  • Stomach pain
  • Nasal congestion or a runny nose
  • Sneezing
  • Slight, dry cough
  • Odd taste in mouth

Severe symptoms may include one or more of the following

  • Swelling of the lips, tongue, and/or throat that blocks breathing
  • Trouble swallowing
  • Shortness of breath or wheezing
  • Turning blue
  • Drop in blood pressure (feeling faint, confused, weak, passing out)
  • Loss of consciousness
  • Chest pain
  • A weak or “thready” pulse
  • Sense of “impending doom”

Severe symptoms, alone or combined with milder symptoms, may be signs of life-threatening anaphylaxis. This requires immediate treatment.

Epinephrine is the first-line treatment for anaphylaxis, and your anaphylaxis plan should be individualized by your healthcare provider. Delays in administering epinephrine for severe or persistent symptoms can be very dangerous, especially when the delay is an hour or longer.

For an educational poster to share with others about mild and severe symptoms of a food allergy reaction, click here