Full Body Rash After Eating

A full body rash that occurs after you eat is a serious sign of a severe allergic reaction. You need to call your doctor or 911 immediately to prevent further complications. Around 90 percent of all food allergies are related to fish, shellfish, soy, tree nuts, wheat, peanuts, milk and eggs. If you've been diagnosed with a specific food allergy, such as an allergy to milk, you need to eliminate the allergen completely from your diet. Consuming even a small amount of the food can trigger a severe allergic reaction.

Welts on an arm Credit: konmesa/iStock/Getty Images

Full Body Rash

A full body rash from eating is most likely hives. Hives are a common allergic skin condition that can appear within minutes of eating a food that causes an allergic reaction. The rash forms in one part of your body and spreads in a matter of minutes. Hives are very itchy and first appear like welts that can connect and form large patches or inflamed, red and swollen skin. A full body rash from eating is concerning because it is a sign that the allergic reaction is affecting your entire body. This can cause significant complications in your respiratory system, digestive system and cardiovascular system.


The entire body skin rash is caused by a systemic reaction that triggers the production of excessive amounts of antibodies and histamine. Your immune system reacts to the proteins in the food as if they are dangerous. Histamine protects the body from infectious diseases, but during an allergic reaction, excessive amounts of histamine cause inflammation. Inflammation in various parts of the body is what causes the entire body skin rash and other anaphylaxis symptoms.

Other Signs

If you're experiencing a severe allergic reaction, anaphylaxis, you will develop other signs and symptoms along with the full body rash. Other symptoms that may develop is shortness of breath, wheezing, coughing, the inability to breathe, dizziness, lightheadedness, increased heart rate, fainting, nausea, abdominal pain, metallic taste in your mouth, vomiting and diarrhea. Symptoms can develop quickly and can lead to death if not treated right away. Call 911 if you notice any of these symptoms.


An all body skin rash after eating from a severe allergic reaction may need an injection of epinephrine. Epinephrine is a synthetic adrenalin that will calm the various systems in the body and restore your ability to breathe and function normally. If the rash persists, your doctor may prescribe a corticosteroid to reduce the inflammation in the skin.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.
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