🦑Mollusc allergy
Molluscs — squid, octopus, cuttlefish, mussels, clams, oysters, scallops and snails — are one of the 14 major allergens in the EU and UK. A mollusc allergy can cause severe reactions and usually lasts, so it is managed by avoiding molluscs completely and being ready to treat a reaction.
🔬What it means
The immune system mistakes mollusc proteins for a threat and releases chemicals such as histamine. Even a small amount can trigger a reaction in some people.
Molluscs and crustaceans (shrimp, crab, lobster) are separate allergen groups, but they share similar proteins, so some people react to both. Others react to only one. Fish allergy is a different allergy. Only an allergist can tell you which seafood is safe — do not test it yourself.
✅What you can eat
Everything that does not contain molluscs or traces of them. Plain meat, eggs, dairy, grains, fruit and vegetables are naturally free of them. Whether fish and crustaceans are safe depends on your own tests — ask your allergist.
🚫What to avoid
- 🦑Molluscs in any form: squid (calamari), octopus, cuttlefish, mussels, clams, cockles, oysters, scallops, whelks, abalone, snails (escargots).
- 🥘Dishes where they are usual: paella, moules marinières, spaghetti alle vongole, fried calamari, fritto misto, seafood risotto and pasta, squid-ink dishes, takoyaki, clam chowder, sushi and seafood salads.
- 🥫Hidden sources: oyster sauce (common in Chinese and Thai stir-fries), XO sauce (dried scallop), seafood stock and flavourings.
- 🏷️Labels: in the EU and UK molluscs must be highlighted in the ingredients. “May contain molluscs” means there is a risk of traces — most allergists advise avoiding these products.
- 🍽️Cross-contact: shared fryers, grills and pans in seafood restaurants and fish markets. Tell the staff about the allergy every time.
⚠️What happens during a reaction
Symptoms usually start within minutes to two hours: itchy mouth, hives, redness, swelling of the lips or face, stomach pain, vomiting, sneezing or a runny nose.
A severe reaction — anaphylaxis — affects breathing or circulation: swelling of the tongue or throat, hoarse voice, wheezing, difficulty breathing, feeling faint, pale or clammy skin, collapse. It can develop fast and is life-threatening.
Feeling ill after shellfish can also be food poisoning, which can affect anyone. If you are not sure which it was, see a doctor before eating molluscs again.
🚑When to get help urgently
If there are any signs of anaphylaxis, use an adrenaline auto-injector if you have one and call emergency services immediately, even if symptoms improve. Lie down with legs raised (or sit up if it is hard to breathe) and do not stand up suddenly. After any reaction, see a doctor about an allergy plan.
📱How Me Nutrition helps
Every dish in the app and on this site shows the major allergens of a typical recipe, including molluscs, and which ingredient contains them. Recipes differ and traces are not covered, so always check with whoever cooked the dish.
Dishes that contain it: 82
Sources
Written from the sources below; not reviewed by a doctor. Not medical advice. How we count →