Pork-Cat Syndrome

Pork-cat syndrome is a condition in which individuals become allergic to pork following exposure and sensitivity to cats.  It almost always occurs in individuals who have or have had cats.

Typically, if one is sensitized to cat allergen, the allergic symptoms one may develop are generally triggered by exposure to the cat allergen from the air.  These allergic rhinitis (i.e., hay fever) symptoms may include itchy eyes, red eyes, watery eyes, sneezing, nasal congestion, runny nose, post-nasal drip, itchy throat, sinus pressure, and/or sinus headaches.  Cat allergen may also trigger and/or aggravate asthma symptoms in some individuals and cause coughing, wheezing, chest tightness, and/or shortness of breath.  The treatment for classic cat allergies includes avoiding exposure to cats, medications to relieve the symptoms, and/or allergy immunotherapy (i.e., allergy injections, allergy shots, allergy desensitization, allergy hyposensitization).  Medications may include oral antihistamines, oral decongestants, leukotriene antagonists, nasal corticosteroids, nasal antihistamines, nasal anticholinergics, nasal mast cell stabilizers, ocular antihistamines, and/or ocular mast cell stabilizers.  The use of oral corticosteroids, nasal decongestants, ocular corticosteroids, and ocular decongestants are discouraged due to their side effects and/or “addictive” qualities.

What is common between cat and pork allergies?

Cat-allergic individuals are also more likely to develop food allergies, particularly to meat, than that of the general population.  The most common type of food allergy related to a history of a cat allergy is that of an allergic reaction to pork.  The symptoms generally begin within an hour after the ingestion of pork.  The usual symptoms may include generalized itching (i.e., pruritus) and/or breaking out in hives (urticaria).  These symptoms can be followed by abdominal cramping, nausea, and diarrhea.  Rarely, more severe reactions such as a sudden drop in blood pressure or throat swelling, which can cause a difficulty in swallowing or breathing, or life-threatening anaphylaxis may occur.  Needless to say, allergic reactions need to be quickly identified and treated with medications in order to stop them from progressing to anaphylaxis.  As meat allergies cannot be desensitized at this time, sensitized individuals should avoid exposure to meat at all times.

The reason that some cat-sensitized individuals are susceptible to pork allergies is that some individuals are not only allergic to the cat dander, but are also allergic to a protein found in cats called albumin.  Albumin is also found in meat from pigs and other animals.  The albumins share several common amino acid sequences.  This phenomenon is termed cross species cross-reactivity.  When albumin is consumed after eating pork meat, an allergic reaction may occur in some cat-sensitive individuals (i.e., in patients that are allergic to cat albumin).

The diagnosis is suspected when a person with a history of allergies to cat also reacts to pork.  It is confirmed by the demonstration of the presence of specific antibodies to both cat and pork allergens.  This is accomplished by skin prick testing and/or laboratory tests.  Skin tests with raw pork are usually positive but with baked meat can be negative since the heat often denatures the protein.  An oral food challenge to pork may sometimes be needed to establish the diagnosis.

This condition should be distinguished from the more common allergies to mammalian meat caused by antibodies to a carbohydrate called alpha-gal.  This condition, which is known as mammalian meat allergy, usually follows a tick bite which introduces the allergen into humans.  In this condition, the symptoms usually begin several hours after ingestion of mammal meat (e.g., beef, pork, lamb, venison) as a “delayed anaphylaxis.”  The diagnosis is confirmed by the detection of specific IgE antibodies to alpha-gal in a blood test.  Some individuals with this condition will have their sensitivity reduced after several years of avoiding the ingestion of mammalian meat.

The management of pork-cat syndrome entails reducing exposure to cats as well as avoiding of pork at all times.  Some individuals will be able to tolerate well-cooked pork, as high temperatures can denature the offending protein and render it less harmful.  Most patients with this condition also need to carry self-injectable epinephrine for emergency use in case of a severe reaction after the accidental exposure to pork.

The board certified allergy doctors at Black & Kletz Allergy have 3 office locations in the Washington, Northern Virginia, and Maryland metropolitan area.  The allergy specialists at Black & Kletz Allergy treat both pediatric and adult patients.  We have offices in Washington, DC, McLean, VA (Tysons Corner, VA), and Manassas, VA.  All 3 of our offices have on-site parking and both the Washington, DC and McLean, VA offices are Metro accessible.  In addition, the McLean, VA office has a complementary shuttle that runs between our office and the Spring Hill metro station on the silver line.   For an appointment, please call our office or alternatively, you can click Request an Appointment and we will respond within 24 hours by the next business day.  The allergists at Black & Kletz Allergy have been helping patients with food allergies, hay fever, asthma, eczema, sinus disease, hives, insect sting allergies, immunological disorders, and medication allergies for over a half a century.  If you suffer from any allergy, whether unusual or not, it is our mission to improve your quality of life by reducing or preventing your unwanted and bothersome allergy symptoms.