Allergy to Shellfish

Shellfish allergy — to crustaceans like shrimp, crab and lobster, and mollusks like clams, oysters and scallops — is among the most common food allergies in adults, and unlike many childhood allergies it often appears later in life and persists. Even vapors from cooking shellfish can trigger symptoms in highly sensitive patients.

Common symptoms

• Hives, itching or eczema
• Swelling of the lips, face or throat
• Wheezing, congestion or trouble breathing
• Abdominal pain, nausea or vomiting
• Dizziness or anaphylaxis

Diagnosis & treatment

Skin and blood testing distinguish a true shellfish allergy from other seafood reactions. Crustacean and mollusk allergies do not always overlap, so testing clarifies what must be avoided. Patients with severe reactions should avoid seafood restaurants where cross-contact is likely and carry an epinephrine auto-injector.