SymptomsBy Mayo Clinic staff
Shellfish allergy symptoms generally develop within minutes of eating shellfish and include:
- Hives, itching or eczema
- Swelling of the lips, face, tongue and throat, or other parts of the body
- Wheezing, nasal congestion or trouble breathing
- Abdominal pain, diarrhea, nausea or vomiting
- Dizziness, lightheadedness or fainting
- Tingling in the mouth
A severe allergic reaction to shellfish called anaphylaxis can be life-threatening if it interferes with your breathing. An anaphylactic reaction is a medical emergency that requires treatment with an epinephrine (adrenaline) injection and a trip to the emergency room. Signs and symptoms of anaphylaxis include:
- A swollen throat or a lump in your throat (airway constriction) that makes it difficult for you to breathe
- Shock, with a severe drop in your blood pressure
- Rapid pulse
- Dizziness, lightheadedness or loss of consciousness
Though they share similar symptoms, a shellfish allergy is different from an adverse reaction to toxins or bacteria in your food. Unlike an allergy, food poisoning doesn't directly involve your immune system and occurs only when you eat food that has been contaminated. An allergic reaction to shellfish usually occurs every time you eat the type of shellfish that causes the reaction.
When to see a doctor
See a doctor or allergy specialist if you have food allergy symptoms shortly after eating. Seek emergency treatment if you develop any signs or symptoms of anaphylaxis.
- Lopata AL, et al. Shellfish allergy. Clinical & Experimental Allergy. 2010;40: 850.
- Lopata AL, et al. New insights into seafood allergy. Current Opinion in Allergy and Clinical Immunology. 2009;9:270.
- Sicherer SH. Seafood allergies: Fish and shellfish. http://www.uptodate.com/home/index.html. Accessed April 5, 2011.
- Atopic and allergic disorders. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merckmanuals.com/professional/sec13/ch165/ch165c.html?qt=seadfood%20allergy&alt=sh. Accessed April 8, 2011.
- Seafood allergy. American Academy of Allergy, Asthma & Immunology. http://www.aaaai.org/patients/advocate/2006/winter/seafood.asp. Accessed April 8, 2011.
- Kurowski K, et al. Food allergies: Detection and management. American Family Physician. 2008;77:1678.