People with food allergies have an allergic reaction when they come in contact with certain foods. This happens because their immune system overreacts to the proteins in that food. 

Eight kinds of food cause most food allergies: 
• Cow’s milk
• Eggs
• Peanuts
• Wheat
• Soy
• Fish
• Shellfish
• Tree nuts

Signs of a food allergy include:
• A rash, or red, itchy skin
• Stuffy or itchy nose, sneezing, or itchy and teary eyes
• Vomiting, stomach cramps or diarrhea
• Swelling
• Hoarseness, throat tightness or a lump in the throat
• Wheezing, chest tightness or trouble breathing

Some people with food allergies can have a serious reaction called anaphylaxis.