A fish allergy is not exactly the same as a seafood allergy. Seafood includes fish (like tuna or cod) and shellfish (like lobster or clams). Even though they both fall into the category of "seafood," fish and shellfish are biologically different. So shellfish will only cause an allergic reaction in someone with a fish allergy if that person also has a shellfish allergy.
People with a fish allergy might be allergic to some types of fish but not others. Although most allergic reactions to fish happen when someone eats fish, sometimes people can react to touching fish or breathing in vapors from cooking fish.
Fish allergy can develop at any age. Even people who have eaten fish in the past can develop an allergy. Some people outgrow certain food allergies over time. But those with fish allergies usually have that allergy for the rest of their lives.
What Are the Signs & Symptoms of a Fish Allergy?
When someone is allergic to fish, the body's immune system, which normally fights infections, overreacts to proteins in the fish. Every time the person eats (or, in some cases, handles or breathes in) fish, the body thinks these proteins are harmful invaders and releases chemicals like . This can cause symptoms such as:
a drop in blood pressure, causing lightheadedness or loss of consciousness (passing out)
Allergic reactions to fish can differ. Sometimes the same person can react differently at different times. Fish allergy can cause a severe reaction called anaphylaxis, even if a previous reaction was mild. Anaphylaxis might start with some of the same symptoms as a less severe reaction, but can quickly get worse. The person may have trouble breathing or pass out. More than one part of the body might be involved. If it isn't treated, anaphylaxis can be life-threatening.
A child who has a fish allergy must completely avoid eating fish. Sometimes an allergist can test for allergies to specific types of fish. Otherwise, it's best for someone with a fish allergy to avoid all fish.
How Is an Allergic Reaction to Fish Treated?
If your child has a fish allergy (or any kind of serious food allergy), the doctor will want him or her to carry an epinephrine auto-injector in case of an emergency.
An epinephrine auto-injector is a prescription medicine that comes in a small, easy-to-carry container. It's easy to use. Your doctor will show you how. Kids who are old enough can be taught how to give themselves the injection. If they carry the epinephrine, it should be nearby, not left in a locker or in the nurse's office.
Wherever your child is, caregivers should always know where the epinephrine is, have easy access to it, and know how to give the shot. Staff at your child's school should know about the allergy and have an action plan in place. Your child's medicines should be accessible at all times. Also consider having your child wear a medical alert bracelet.
Every second counts in an allergic reaction. If your child starts having serious allergic symptoms, like swelling of the mouth or throat or difficulty breathing, give the epinephrine auto-injector right away. Also give it right away if the symptoms involve two different parts of the body, like hives with vomiting. Then call 911 and take your child to the emergency room. Your child needs to be under medical supervision because even if the worst seems to have passed, a second wave of serious symptoms can happen.
It's also a good idea to carry an over-the-counter (OTC) antihistamine for your child, as this can help treat mild allergy symptoms. Use after — not as a replacement for — the epinephrine shot during life-threatening reactions.
What Else Should I Know?
If allergy testing shows that your child has a fish allergy, the doctor will give you guidelines on keeping your child safe. To prevent allergic reactions, your child must not eat fish. Your child also must not eat any foods that might contain fish as ingredients. Anyone who is sensitive to the smell of cooking fish should avoid restaurants and other areas where fish is being cooked.
Always read food labels to see if a food contains fish. Manufacturers of foods sold in the United States must state whether foods contain any of the top eight most common allergens, including fish. The label should list "fish" in the ingredient list or say "Contains fish" after the list.
Some foods look OK from the ingredient list, but while being made they can come in contact with fish. This is called cross-contamination. Look for advisory statements such as "May contain fish," "Processed in a facility that also processes fish," or "Manufactured on equipment also used for fish." Not all companies label for cross-contamination, so if in doubt, call or email the company to be sure.
Cross-contamination often happens in restaurants. In kitchens, fish can get into a food product because the staff use the same surfaces, utensils (like knives, cutting boards, or pans), or oil to prepare both fish and other foods.
This is particularly common in seafood restaurants, so some people find it safer to avoid these restaurants. Fish is also used in a lot of Asian cooking, so there's a risk of cross-contamination in Chinese, Vietnamese, Thai, or Japanese restaurants. When eating at restaurants, it may be best to avoid fried foods because many places cook chicken, French fries, and fish in the same oil.
When eating away from home, make sure you have an epinephrine auto-injector with you and that it hasn't expired. Also, tell the people preparing or serving your child's food about the fish allergy. Sometimes, you may want to bring food with you that you know is safe. Don't eat at the restaurant if the chef, manager, or owner seems uncomfortable with your request for a safe meal.
Also talk to the staff at school about cross-contamination risks for foods in the cafeteria. It may be best to pack lunches at home so you can control what's in them.
Other things to keep in mind:
Make sure the epinephrine auto-injector is always on hand and that it is not expired.
Don't feed your child cooked foods you didn't make yourself or anything with unknown ingredients.
Carry a personalized "chef card" for your child, which can be given to the kitchen staff. The card details your child's allergies for food preparers. Food allergy websites provide printable chef card forms in many different languages.
Tell everyone who handles the food — from relatives to restaurant staff — that your child has a fish allergy.