Once a shellfish allergy is identified, the best treatment is to avoid the food. You need to carefully check ingredient labels of food products. You should learn other names for the foods you need to avoid to be sure not to eat them.
You must be extra-careful when you eat out. Waiters (and sometimes the kitchen staff) may not always know every dish ingredient on the restaurant’s menu. Vapors may carry extremely small particles of shellfish protein, so even just walking into a kitchen or other area where food is being prepared can cause a dangerous reaction in sensitive individuals.
Fortunately, shellfish is an ingredient that is rarely “hidden” in foods. Shellfish may be found in fish stock, seafood flavoring (for example, crab extract), sushi and surimi. In the U.S., if a packaged food contains shellfish, labeling regulations require the specific shellfish be listed. (Note: Those regulations apply only to crustacean shellfish, such as shrimp, lobster and crab, and not to mollusks, such as oysters, scallops and clams.)
Patients with any food allergy must make some changes in the foods they eat. Your allergist can direct you to helpful resources, such as special cookbooks, patient support groups and registered dietitians, who can help you plan your meals.
Many people with food allergies wonder if their condition is permanent. There is no clear-cut answer. Over time, allergies to milk, eggs and soy may disappear. Allergies to peanuts, tree nuts, fish and shellfish typically last a lifetime. About one-third of the children and adults who had food allergies at some point are eventually free of them after very carefully avoiding the foods.
Managing a severe food reaction with epinephrine
Shellfish is among the most common food allergens. It is also the most dangerous, sending more allergic people to hospital emergency rooms for treatment than any other food.
Epinephrine is the first-line treatment for anaphylaxis, a rare but severe whole-body allergic reaction that causes severe symptoms, including tightening of the airway. Anaphylaxis can occur within seconds or minutes of exposure to the allergen, can worsen quickly, and can be deadly.
Once a food allergy diagnosis is made, your allergist likely will prescribe an epinephrine auto-injector and teach you how to use it. Check the expiration date of your auto-injector, note the expiration date on your calendar and ask your pharmacy about reminder services for prescription renewals.
Be sure to have two doses available, as the severe reaction may recur. If you’ve had a history of severe reactions, take epinephrine as soon as you suspect you’ve eaten an allergy-causing food, or if you feel a reaction starting. Epinephrine should be used immediately if you experience severe symptoms such as shortness of breath, repetitive coughing, weak pulse, generalized hives, tightness in the throat, trouble breathing or swallowing, or a combination of symptoms from different body areas such as hives, rashes or swelling on the skin coupled with vomiting, diarrhea or abdominal pain. Repeated doses of epinephrine may be necessary.
If you are uncertain whether a reaction warrants epinephrine, use it right away, because the benefits of epinephrine far outweigh the risk that a dose may not have been necessary.
Common side effects of epinephrine may include anxiety, restlessness, dizziness and shakiness. Rarely, the medication can lead to an abnormal heart rate or rhythm, a heart attack, a sharp increase in blood pressure and fluid buildup in the lungs. Patients with certain pre-existing conditions who may be at higher risk for adverse effects should speak to their allergist about epinephrine use.
Your allergist will provide you with a written emergency treatment plan that outlines which medications should be administered and when (note that between 10 and 20 percent of life-threatening severe allergic reactions have no skin symptoms). Be sure you understand how to properly and promptly use an epinephrine auto-injector.
Once epinephrine has been administered, immediately call 911 and inform the dispatcher that epinephrine was given and that more may be needed from the emergency responders.
Other medications, such as antihistamine and corticosteroids, may be prescribed to treat symptoms of a food allergy, but it is important to note that there is no substitute for epinephrine — this is the only medication that can reverse the life-threatening symptoms of anaphylaxis.
Managing shellfish allergies in children
Because fatal and near-fatal shellfish allergy reactions, like other food allergy symptoms, can develop when a child is not with his or her parents, parents need to make sure that their child’s school, day care or other program has a written emergency action plan with instructions on preventing, recognizing and managing these episodes in class and during activities such as sporting events and field trips. A nonprofit group, Food Allergy Research & Education, has a list of resources for schools, parents and students in managing food allergies.
If your child has been prescribed an auto-injector, be sure that you and those responsible for supervising your child understand how to use it.