Swollen Lips as an Allergic Reaction to Peanut Butter

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Nut allergies are among the most common food allergies, and peanut allergies particularly can be dangerous. One symptom of a potentially life-threatening allergic reaction is swelling of the mouth, lips and tongue. If this happens to you or someone you are with after eating peanut butter or any other food, call 911 or visit the emergency room immediately.

Peanut Allergies

Your body may react to peanuts or peanut butter even if you have eaten these foods for years with no problem. No one knows why some people develop allergies to peanuts, but once they occur, they are usually with you for life. While some children grow out of allergies to foods like wheat and milk, most peanut allergies don't go away. You may have reactions just if you eat peanuts or peanut butter, but you also might react if someone else eats peanut butter near you and you inhale some of the peanut proteins.


Peanut allergy reactions can be mild or severe. Mild reactions include rashes, hives, nausea, vomiting, diarrhea and a runny or stuffy nose. Moderate reactions may include some facial swelling, lightheadedness and coughing or wheezing. If you have a moderate reaction after ingesting peanut butter, seek medical care right away, as it could lead to a more severe reaction called anaphylactic shock. You might have a mild reaction the first time you are exposed to an allergen -- but you can experience a severe reaction the next time.

Anaphylactic Shock

In severe cases, a peanut allergy can cause anaphylactic shock, which entails a medical emergency. As your body reacts to the allergen, you may experience swelling of the mouth and throat, you may find it hard to breathe and your blood pressure may drop, causing fainting. If you have had this type of reaction or your doctor thinks this may happen to you, he will prescribe an epinephrine autoinjector, an injection of epinephrine to use in case of emergency. Your doctor will explain how and when to use this treatment, and what the next course of action should be if you experience anaphylactic shock.

Avoiding Problems

If you know that you are allergic to peanuts, the best way to avoid a severe reaction is to be aware of what you eat. Read food labels carefully to ensure that foods you eat do not contain peanuts. Also, make note of whether your food is prepared on machinery or in a facility that also processes peanut products; find this information under the ingredients list. See an allergist for more information on avoiding peanuts in your daily life if you are prone to a severe allergic reaction.