A food allergy is when you eat something harmless, and your immune system mistakes it for something that could make you sick. In such cases, the immune system responds harshly to protect you. Common allergic food reactions are skin rash, itchy eyes, or serious consequences that could leave you gasping for air. While any kind of food can cause allergic reactions, most of them are caused by these five common foods mentioned below.

Peanuts
Peanuts are one of the most common allergic foods that can be fatal. The exact reason why people develop peanut allergy is unknown, but those with a family history of the same are considered at risk. Peanut allergy is diagnosed using patient history, skin pricking tests, blood tests, and food challenges. About 15-22% of children who develop peanut allergies are unaffected once they enter teenage.

Tree nuts
People with nut allergies should avoid all types of tree nuts. The risk to one type increases the risk of developing a food allergy to all others. Examples of tree nuts are Brazil nuts, almonds, cashews, and macadamia nuts. Tree nut allergies are responsible for about 50% of anaphylaxis-related deaths. Hence, people with this allergy should carry an epi-pen at all times.

Eggs
Eggs are the second most common food allergy in children, but more than half outgrow it after they turn 16. Symptoms of egg allergy are stomach ache, skin rash or hives, respiratory problems, and anaphylaxis (rare). Heating eggs can change the shape of allergy-causing proteins, so you may not have to eliminate all egg-related foods.

Cow milk
Allergy to cow milk is commonly seen in babies and children. This kind of reaction can occur in IgE and non-IgE forms. In adults or children with IgE, reactions occur within 5-30 minutes. Symptoms are swelling, rashes, hives, and vomiting. A non-IgE case experiences gut-based symptoms like constipation, vomiting, diarrhea, and inflammation of the gut wall.

Shellfish
Shellfish allergy happens when the immune system attacks proteins from crustacean and mollusk families of fishes, commonly called shellfish. Shrimp, prawns, crayfish, lobster, squid, and scallops are some examples of shellfish. Tropomyosin, arginine kinase, and myosin light chain proteins found in seafood may also trigger a food allergy reaction.

Peanut allergy immunotherapy
This course helps in building immunity against peanuts in allergic patients. The doctor slowly introduces a small amount of peanut protein and then moves to a large quantity until the target is complete. Peanut allergy immunotherapy helps desensitize individuals to peanut protein, especially those affected with life-threatening anaphylaxis.