When people eat food they're allergic to, they often suffer some type of skin rash as a result, according to the American Academy of Family Physicians. A variety of foods---from eggs and milk to peanuts and shellfish---may trigger allergies that cause skin rashes. Three different types of skin rashes may occur from food allergies.
Urticaria
Urticaria, commonly known as hives or welts, shows up on skin as raised red or pink lesions that itch. The lesions usually appear about one hour after people eat or otherwise come into contact with food containing a substance they're allergic to, notes AAFP. A group of lesions usually lasts a few hours before disappearing, notes Skinsight.com, but new lesion groups can appear after older groups have faded away, and many people experience the condition for a period of time that lasts between a few days and a few weeks. AAFP adds that just slightly more than 1 percent of urticaria cases that last longer than six weeks are caused by food allergies.
Atopic Dermatitis
Atopic dermatitis, which is also called eczema, is associated with food allergies and may be indirectly caused by them, according to the American Academy of Dermatology. Food allergies do seem to cause atopic dermatitis, especially in children, AAFP reports, but exactly how they do isn't yet understood. About 37 percent of children who suffer from atopic dermatitis also have food allergies, notes AAFP. Foods commonly associated with allergies that may contribute to atopic dermatitis include nuts, shellfish such as shrimp and crab, and milk and dairy products like yogurt and cheese.
Dermatitis Herpetiformis
Dermatitis herpetiformis appears as lesions on the skin of people's knees, buttocks and elbows. This skin rash is associated with an allergy to gluten, a protein that's found in grains such as wheat, oats, rye and barley. When people with dermatitis herpetiformis rashes who are allergic to gluten eliminate gluten from their diets, their rashes go away, according to AAFP.
