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Allergy to Animals

Pet AllergiesAllergic reactions to animals can be a significant cause of severe allergic symptoms. The allergy causing substances from animals are contained in the sebaceous glands of the cat’s skin or in the dander (the surface layer of skin cells), saliva or urine of dogs and rodents. The allergen particles are so small they cannot be seen in the household environment, but eventually they penetrate the rugs and bedding. Animal fur itself is not considered to be a major cause of allergy.


The symptoms resulting from allergy to animals can involve the nose, eyes and lungs. The nasal symptoms present like hay fever and the lung symptoms present like asthma.

  • Nasal symptoms include mild nasal symptoms such as sneezing or congestion.
  • Lung symptoms can range from low grade coughing or wheezing to severe asthma. This asthma may persist for hours or even days after being away from the animal.

As with other types of allergies, a diagnosis can be confirmed by correlation of the history with the results of skin tests.

What You Can Do

In cases were the animal causes significant disease, elimination of the pet from the home may be the only sound treatment. An animal that is kept totally outside of the house should not be a problem. If the pet cannot be removed from the house, several secondary measures are recommended:

  • Keeping the pet out of the allergic individual’s bedroom.
  • Running a HEPA filter in the bedroom continuously to filter the allergen from the air.
  • Washing the pet one or two times a week.

These interventions have been shown to reduce the amount of pet allergen in the bedroom.

A variety of medications may be used in the management of allergy to animals, but they may not provide adequate relief in all cases. Allergy injections to protect against cats may be effective but are not considered the treatment of choice. Animal allergy, particularly due to cats, may be far more important than a patient can recognize. This is because the animal protein has become part of the home environment and can produce continuous symptoms.

Individuals may become extremely fond of their pets. Realizing this, advice to pet from the home is given only after due consideration of the psychological impact on the patient and his/her family. However, sometimes it is necessary to advise removal of a household pet in order to assure the best possible care for patients and to prevent the development of irreversible asthma.

Allergic individuals or their families who have histories of multiple allergies to pollens, molds or dust are at an increased risk for developing allergies to animals once introduced into the house, and therefore they should consider this carefully before obtaining an animal for their home. It may be more difficult to remove a pet from the home after an emotional attachment has developed than to avoid getting one in the first place.

It is important to mention that cat allergen can be passively transferred on clothing and shoes so homes without cats can still have detectable levels of allergen. Encasements over the pillow and mattress are also helpful in reducing allergen exposure. In families where it is not possible to get rid of the pet from the home, creating a clean room in the bedroom and main activity room is advised. Keep pets out of these rooms, vacuum regularly and put HEPA filters in each room. Allergy injections may help to reduce symptoms associated with pet exposure as well.

For more information:

Go to the Allergies health topic.