Even if you’ve never had shellfish allergy symptoms before, you could suddenly develop a shellfish allergy as an adult. In fact, 60 percent of people with shellfish allergies develop it later in life, even if they have eaten shellfish since they were young. Your chances of developing a shellfish allergy increase to 30 or 40 percent if one of your parents has a food allergy, and to 75 percent if both of your parents are allergic. Once you have a shellfish allergy, you are likely to be stuck with it for life.
If you notice shellfish allergy symptoms within minutes or hours after you eat shellfish, it may be a sign of an allergy. Symptoms to look out for include hives, itching or swelling, difficulty breathing, nausea, vomiting, diarrhea or dizziness. A more dangerous symptom that requires immediate medical attention is anaphylaxis. Anaphylaxis is characterized by a swollen throat that makes it difficult to breathe; decrease in blood pressure; fast pulse; and dizziness or loss of consciousness. Anaphylactic shock is potentially fatal, so it’s important to recognize the symptoms and get help right away.
Shellfish allergies are usually triggered by ingestion of one or more types of shellfish. Depending on the severity of your allergy, even shellfish remnants in your diet can trigger a reaction. That’s why it’s important to check the labels on the food you buy to make sure it doesn’t contain shellfish. In restaurants, it’s a good idea to find out what you’re ordering — even if you’re not ordering shellfish directly. Sometimes, clams are fried in the same oil as french fries, for example. For some people who are very sensitive, simply feeding the clams or inhaling the steam from cooking clams is enough to trigger an allergic reaction.