Crab Allergy Symptoms

Crab Allergy Symptoms

Crab allergy is a of the most common food allergies in adults. It produces some of the most severe reactions and is considered long-term. People allergic to crabs usually also have allergies to other crustaceans, as reported by the American Academy of Allergy, Asthma and Immunology, or AAAAI. It is also common for shellfish dishes that do not contain crabs to cross-contaminate allergens. Doctors should advise their patients to avoid eating or handling other seafood. The allergic reaction to the crab can occur when the person touches, eats or tastes food with crabs or when breathing the cooking vapors. Symptoms vary from moderate to life-threatening.

Tingling in the mouth

People who are allergic to crabs may initially experience a tingling sensation in their mouth after eating them. Even a small amount of allergens can cause this sensation. Although there is no obvious presence of crabs on the plate, cross contamination can occur at the time the food is processed, prepared or cooked.

Urticaria and inflammation

Individuals who are allergic to crabs may suffer symptoms related to urticaria. This produces red, inflamed and itchy skin hives that last from 2 to 4 hours. It usually appears when people stop handling or eating crabs. Angioedema, or excessive swelling of the lips, mouth or throat, can occur immediately after eating the crabs, says Dr. Lopata in the April 2010 issue of the Clinical and Experimental Allergy. Inflammation on the entire face or in a large part of the body may indicate a more serious reaction.


The eczema begins as very small lumps like pimples that itch a lot and dry. When scratching, inflamed, thick and scaly rashes occur that get worse over time. Eczema often occurs in people who work in crab or shellfish processing plants, or in those who handle seafood in their work, according to Dr. Lopata.


Asthma also occurs when a person sensitive to crabs touches, eats or inhales cooking vapors contaminated with them. Symptoms of asthma include wheezing, tightness in the chest, difficulty breathing and coughing. This condition can also occur in the workplace, such as processing plants or seafood restaurants. The Asthma and Allergy Foundation of America states that wheezing may occur minutes after exposure and disappear after 1 to 2 hours after leaving the workplace. A delayed allergic reaction can occur 3 to 8 hours after exposure and exacerbate at night.Patients with asthma or allergic reaction to crabs should inform their doctor if they suspect that asthma is related to their work.


Anaphylaxis is an allergic reaction to crabs and other severe and life-threatening shellfish. It affects the whole body and causes the blood pressure to fall. Symptoms vary and can occur all together: red skin, rashes, swelling of tissues and joints, wheezing, nausea, abdominal cramps, rapid pulse, convulsions and fainting. According to the AAFA, intense exercise after eating crabs can cause anaphylaxis. People allergic to these seafood require immediate medical attention when the symptoms of anaphylaxis begin to occur.

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