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Medical Author:

Jatinder Singh, MD

Coauthor:

Mark Clark, MD

Medical Editor:

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, Chief Medical Editor

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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A person with a food allergy can have symptoms beginning as soon as 2 minutes after eating the food, but reactions may take 1 to 2 hours to appear. Occasionally, symptoms abate quickly, only to recur in 3 to 4 hours.

• The most common symptoms include the following:
• Itching of the skin followed by hives, a rash of raised, reddish bumps or wheals
• Swelling of the lips and mouth
• Belly cramps
• Nausea
• Vomiting
• Diarrhea
• Other symptoms may include the following:
• Itching and watering in the eyes
• Runny or stuffy nose
• Symptoms of a more severe reaction could include the following:
• Shortness of breath or difficulty breathing
• Tightness in the chest
• Feeling of tightness or choking in the throat
• Rapid or irregular heart beat
• Feeling dizzy or light-headed
• Losing consciousness
• A severe allergic reaction can be life threatening. This severe reaction is referred to as anaphylaxis, or anaphylactic shock.
• The dizziness, lightheadedness, and loss of consciousness are due to dangerously low blood pressure, called "shock."
• An anaphylactic reaction can begin suddenly, or it may develop gradually with itchiness and swelling of the skin and throat and then progress to a severe reaction over a few hours.
• Most people get such a reaction immediately after eating the food, but in a few unusual cases the reaction occurs only after exercising following the ingestion of the food.
• Severe reactions are most often seen with allergies to nuts, fish, and shellfish, although allergy to any food can cause anaphylaxis.
• People with asthma, childhood allergies, eczema, or prior severe food allergies are especially at risk for having an anaphylactic reaction.
• MSG reaction can be mistaken for an allergic reaction.
• Symptoms of MSG reaction include the following:
• Burning sensation at the back of the neck and radiating down the arms and chest
• Tingling and numbness in the same areas
• Headache
• Nausea
• Occasionally, difficulty breathing, especially in those with poorly-controlled asthma
• A few people experience seizures, irregular heartbeats, and anaphylaxis after the use of MSG.
• Contrary to popular beliefs, MSG has no relation to Alzheimer disease, Huntington chorea, or other chronic illnesses.

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