What should you know about drugs to avoid with shellfish allergy?

Shellfish allergy is usually triggered by proteins in shellfish. Iodine is a naturally occurring element, not the shellfish protein that causes the allergy, so an allergy to prawns, crab or other shellfish does not by itself predict a reaction to iodine, antiseptics or contrast used in imaging. Some medicines can still cause an independent drug allergy, and a product may contain an animal-derived ingredient or shellfish-related supplement. The medicine name alone cannot answer that question.

Tell every doctor, dentist and pharmacist about the exact shellfish reaction you had. A rash, wheeze, vomiting or collapse after eating shellfish is different from an intolerance, and the distinction affects safety planning.

Before starting a prescription, over-the-counter product or supplement, show the package and your allergy history to a pharmacist. Ask about the active ingredients, inactive ingredients and whether the product is appropriate for you. Do not stop a prescribed medicine suddenly or reject an imaging test solely because it involves iodine. If you have reacted to a medicine before, record its name, the reaction and when it happened; a GP can arrange an assessment or refer you for Allergy Testing.

Keep any emergency medicine prescribed for a previous severe reaction available, and follow the personal action plan you were given. A GP Consultation can help clarify uncertain reactions and document them accurately.

Seek emergency help immediately for trouble breathing, throat or tongue swelling, faintness, confusion, widespread hives with other symptoms, or repeated vomiting after a possible allergen or medicine. Use prescribed adrenaline according to your action plan while waiting for help. These can be signs of Anaphylaxis and need urgent assessment even if symptoms start to improve.

Ask: Was my previous reaction an allergy or an intolerance? Which medicines or supplements should I list as allergies? Should I carry an emergency action plan? Do I need Allergy Testing, and what should I do before a scan or procedure?