Symptoms

Shellfish allergy symptoms generally develop within minutes to an hour of eating shellfish. They may include:

• Hives, itching or eczema (atopic dermatitis)
• 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

Allergies can cause a severe, potentially life-threatening reaction known as anaphylaxis. An anaphylactic reaction to shellfish or anything else 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
• Dizziness, lightheadedness or loss of consciousness

When to see a doctor

Seek emergency treatment if you develop signs or symptoms of anaphylaxis.

See a doctor or allergy specialist if you have food allergy symptoms shortly after eating.