What Are Some Common Food Allergens?

Peanuts, tree nuts, milk, eggs, wheat, soy, fish and shellfish are the foods that cause the most allergic reactions, explains Food Allergy Research and Education. Only around 5 percent of children and 4 percent of adults are truly allergic to certain foods, although many more suffer dietary intolerance, states WebMD.

Sneezing; a stuffy or runny nose; itchy, watery eyes; swelling; a rash; stomach cramps; and diarrhea indicate a mild allergy, according to Healthline. Difficulty breathing; swelling of the lips, tongue or throat; hives; dizziness or fainting; and nausea or vomiting point to a more serious allergy.

In fish allergies, WebMD points out many people are severely allergic to fresh salmon, tuna and halibut, and being allergic to one kind of fish means a person might turn out to be allergic to other kinds too. The same is true for nuts and shellfish.