Shellfish Allergy – Diagnosis and Treatment
Diagnosis
Doctors use several ways to figure out if a person has a shellfish allergy. First, they ask about the person’s symptoms, such as swelling, hives, or wheezing, especially after eating foods like shrimp, crab, lobster, or other shellfish.
They also review any patterns seen with reactions to foods like mussels, clams, oysters, scallops, squid, or octopus.
Doctors perform physical exams to rule out other problems. Sometimes, food poisoning or other food allergies (like egg allergy) cause similar symptoms, including rashes or trouble breathing.
Because shellfish allergies can lead to serious issues, such as asthma or severe allergic reactions, doctors strive for an accurate diagnosis.
Doctors often perform a skin prick test. They prick the skin with a small amount of shellfish proteins. If a raised bump appears after 15–20 minutes, this usually indicates an allergy.
Doctors can also order blood tests to measure the amount of immunoglobulin E (IgE) antibodies the immune system produces in response to allergens from crustaceans and mollusks.
| Test Type | What It Checks For | Examples of Shellfish Involved |
|---|---|---|
| Skin Prick Test | Signs of an allergic reaction. | Shrimp, crab, lobster, oyster, scallop |
| Blood Test (IgE) | Immune system antibody levels. | Mussel, clam, squid, octopus, abalone, snail |
If results remain unclear, a doctor might conduct an oral food challenge under close supervision to observe symptoms. This helps confirm if someone is allergic to specific types of shellfish.
Accurate identification of a shellfish allergy helps patients manage foods like bouillabaisse, fish stock, or paella that may contain seafood ingredients.
Management and Response
To prevent a shellfish allergy reaction, patients must strictly avoid shellfish. If exposure occurs, antihistamines can help manage mild symptoms like itching or hives by blocking the effects of histamine.
For severe reactions—called anaphylaxis—epinephrine serves as the primary treatment. People at risk should always carry an epinephrine auto-injector and know how to use it immediately if symptoms begin.
Important Steps:
- Carry injectable epinephrine at all times.
- Give epinephrine immediately if signs of anaphylaxis appear.
- Call emergency services after using epinephrine, even if symptoms improve.
Doctors may use corticosteroids to help with ongoing symptoms after the initial reaction.
Getting Ready for Your Visit
How to Prepare Before Your Appointment
Start by writing down your symptoms, even if they don’t seem related to a shellfish allergy. Include any reactions after eating seafood or being exposed to seafood flavoring.
Note any foods you ate, including sauces and side dishes, when symptoms started, and how long they lasted.
List your medications, vitamins, and supplements, as well as their doses. Gather information about any relatives with allergies or asthma, as family history can help.
To guide the conversation, prepare questions to ask. Consider topics like:
- Whether your symptoms are likely caused by an allergy.
- If you need allergy tests or a referral to an allergist.
- When to carry an epinephrine injector.
- How to manage food allergies daily.
- What to know about food labels, cross-contamination, and safe meals at seafood restaurants.
Having this information ready helps you and your doctor make a plan for prevention and treatment.
Questions Your Doctor May Ask
The provider will want details about your symptoms and what happened before and after you ate shellfish. Be ready to talk about:
- When symptoms appeared and their severity.
- What kind of shellfish or fish you ate.
- All foods and drinks consumed during the meal.
- Others at the meal and their reactions.
- Your history of other allergies or asthma.
- Steps taken to manage reactions, like using an allergy action plan or a medical alert bracelet.
This information helps your doctor decide on tests and next steps.
