Most reactions are from peanut, tree nuts, milk, egg, fish, shellfish, wheat, and soy. Symptoms usually appear within 20 minutes of ingestion and nearly always within 2 hours.
Symptoms and signs may vary from pruritus and mild cutaneous eruption to severe anaphylactic respiratory, GI, or cardiovascular (e.g., hypotensive) manifestations.
Epinephrine given by intramuscular injection is the treatment of choice for severe systemic symptoms (anaphylaxis); lesser reactions are managed with a range of therapies from simple withdrawal of suspected food allergen to oral antihistamines.
Patients should be encouraged to obtain medical identification jewelry, be knowledgeable of the incipient signs and symptoms of an allergic reaction, be trained how to use self-injectable epinephrine, and know how to activate emergency response services.
Typical cutaneous findings in food allergy at 30 minutes after ingestion of peanuts
From the collection of Duke University Medical Center; used with permission