Pork Allergy Caused by Allergies to Cats

Pork Cat Syndrome

Allergy to cats is extremely common, occurring in up to 25 percent of people with allergies. Cat allergy is more common than allergy to dog dander, a fact that may be related to the potency of cat hair and dander as an allergen — and because cats generally aren't bathed. The major cat allergen, Fel d 1, is found in cat saliva, in dander from sebaceous glands in the skin, in fur, and in anal sebaceous glands.

Other cat allergens, including albumin (a major protein in the blood), are found in feline urine, saliva and blood.

Meat allergy, such as to beef, pork, poultry and lamb, is relatively uncommon — likely due to the fact that most meat is thoroughly cooked before being eaten. Cooking reduces the allergenic nature of foods by breaking down the proteins responsible for allergic reactions: if the allergen is broken down by heat, then the allergic antibody (IgE) no longer recognizes the protein, and the allergic reaction does not occur.

Allergic reactions to both pork meat and wild boar meat have been reported. Rarely, people with allergy to cat albumin may also be allergic to pork meat. This relationship is termed the pork-cat syndrome and is caused by the similar structures of cat albumin and pork albumin. Because of this similarity, allergic antibodies towards cat albumin cross-react with pork albumin.

Most people who are cat allergic experience symptoms due to the major allergen Fel d 1, and therefore aren’t allergic to pork meat.

Unlike allergic reactions to galactose-alpha-1,3-galactose — a carbohydrate found in mammalian meats, which can cause delayed allergic reactions many hours after consumption of meat — allergic reactions to pork in the pork-cat syndrome occur almost immediately after pork is eaten.

Symptoms most often include urticaria/angioedema, oral allergy syndrome, gastrointestinal symptoms (such as nausea, vomiting and diarrhea) and anaphylaxis. Fresh (undercooked) pork meat or dried and smoked pork products tend to cause more reactions, while well-cooked pork meat causes fewer reactions.

The diagnosis of pork-cat syndrome is suspected in a person who has a history of significant allergic symptoms with cat exposure (such as allergic rhinitis and asthma), and has experienced symptoms of food allergy after eating pork. Allergy testing to cat and pork are positive with either skin testing and/or blood testing.

The treatment of pork-cat syndrome is the strict avoidance of any pork product. When a reaction does occur, however, symptoms would be treated similar to how other food allergic reactions are treated. Injectable epinephrine should be made available to any person who has the pork-cat syndrome, since severe and even fatal reactions have been reported in people with this condition as a result of eating pork.

If a person with pork-cat syndrome avoids cat exposure, it is possible that his allergic antibody levels to cat will decrease over time, and therefore the cross-reaction to pork will also decrease. It's therefore possible that a person with pork-cat syndrome will "outgrow" his pork allergy if cats are avoided. While I have not seen any studies suggesting that treatment with allergen immunotherapy (based on cat albumin) would be helpful at reducing a person’s pork allergy, this would at least seem possible.

Source:

Posthumus J, James HR, Lane CJ, Matos LA, Platts-Mills TAE, Commins SP. Initial Description of Pork-Cat Syndrome in the United States. J Allergy Clin Immunol. 131(3):923-5.

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