An allergic reaction to food can cause mild to serious symptoms such as vomiting or nausea, stomach cramps, indigestion, diarrhea, hives or other skin rashes, headaches, asthma, or stuffy nose, sneezing and runny nose. In extreme cases, food allergy can trigger a severe and life-threatening reaction called anaphylaxis. Some mild symptoms may actually be caused by a food sensitivity rather than an allergic reaction. An allergist can help determine if it is a true allergic reaction. Shellfish, peanuts and tree nuts are the most common food allergies in adults. Milk, eggs, soy, wheat, shellfish, peanuts and tree nuts are the most common food allergies in children.