Shellfish allergies can be very serious, but they aren't necessarily that severe. The acuteness of your shellfish allergies depends on your level of sensitivity and how your body reacts. The way that shellfish allergies work is your body misidentifies certain proteins in shellfish as harmful. It reacts by sending out antibodies to fight off the shellfish allergens; from then on, any time you eat shellfish, your body will do the same thing. People react differently to the fight going on between their bodies and shellfish allergens. Some people get a few hives, while others might go into anaphylactic shock.
Generally, the symptoms of a shellfish allergy are hives, swelling, wheezing, congestion, diarrhea, nausea, vomiting, dizziness or a tingling feeling in your mouth. But occasionally, anaphylaxis results; anaphylaxis is a life-threatening condition identifiable by airway constriction that impedes breathing, lowered blood pressure, a fast pulse, dizziness and even loss of consciousness. If you're prone to anaphylaxis, a shellfish allergy is particularly serious. Upon the first signs of anaphylaxis, medical attention is required. Shellfish allergies, along with peanut and tree nut allergies are the most common causes of anaphylaxis. Considering that shellfish allergies are the most prevalent allergies among adults and the fact that they're lifelong, shellfish allergies have gained a fairly notorious reputation.
One other factor that comes into play when determining how serious a shellfish allergy is what type of seafood you're allergic to. Generally, shellfish are divided into two categories: mollusks and crustaceans. Mollusks include clams, scallops, oysters and calamari, while crustaceans include shrimp, crab and lobster. Some people are only allergic to one type of shellfish, while others are allergic to both. Allergies to crustaceans tend to be more severe than allergies to mollusks. Often, people who are allergic to one category avoid both, just to be safe.