Allergies to cats

 

People are allergic to many things – including cats – and these allergies can manifest themselves in different ways.

Some people will be mildly affected, feeling itchy, snuffly or sneezing; others have severe skin reactions, and a few may experience a serious asthma attack.

These reactions occur because the person’s immune system reacts to particular proteins (antigens) from animals or plants, to produce antibodies and/or other chemicals to protect the body. Antibodies and other immune reactions are part of the body’s normal defence mechanism designed to protect against foreign organisms such as viruses, bacteria and parasites. However, in allergies, this immune response is over-exuberant and often misdirected (targeting proteins or antigens that are not genuinely harmful). During an allergic response, histamine may be inappropriately released from cells on exposure to the antigen, and this can irritate the lungs, nose, skin and other tissues – hence the common reactions of sneezing, coughing, wheezing or itching.

What triggers the allergic response to cats?

The main trigger for the allergic reaction to cats are proteins which are secreted in saliva (Fel d 4) and in the sebaceous glands (Fel d 1) in the skin of all cats. These proteins can be found on the coat of the cat because the cat grooms itself, and so deposits saliva (containing Fel d 4) on the hair, and because the secretions from the sebaceous glands (containing Fel d 1) will also surround the hair. However, the allergy is not to cat hairs themselves. Fel d 4 is also shed in urine and faeces. Entire male cats produce the highest amount of these proteins.

Do all cats provoke an allergic response

In an allergic individual, the signs of a reaction can occur if the allergen is inhaled or a person strokes a cat, cleans its litter tray or even sits where the cat has been sitting. Different individuals have different levels of allergies – some cannot tolerate being in a room where cats have been, whereas in others the reaction may be much more mild.

All breeds of cat produce allergens, but some may produce more than others – it can be a case of trial and error to ascertain which cats you react to (or which you react worst to). Although the reason is not clear, many people seem to react more to longhaired cats – perhaps because more allergen builds up on their fur or accumulates because of more hair around the house. Likewise, even cats with little hair such as Rexes or Sphynx cats still cause reactions as the allergy is not to the cat’s hair itself. As noted above, entire male cats may produce more of the proteins that cause the allergy and are therefore probably a greater risk to an allergic individual, female cats are likely to produce the lowest amounts.

How to reduce the exposure to Fel d 1 and Fel d 4

If you have a cat and are mildly allergic to it, then several steps may help reduce your exposure to Fel d 1 and the severity of the allergy:

  • Keep the cat off your bed and out of your bedroom
  • Try to avoid having the cat in rooms where there is carpet (which can trap hair and dander)
  • Laminate or tiled floors with washable rugs are much more cleanable than wall-to-wall carpets.
  • Try to avoid using soft furnishings (cushions etc) where your cat is allowed, other than those that can be readily washed, and make sure they are washed frequently
  • Vacuum clean the house frequently and thoroughly with a cleaner fitted with a HEPA filter, and make sure the house is well ventilated
  • Use a cat flap and allow your cat to spend time outdoors, do not confine it to the house
  • Using air purifiers
  • Making sure you wash your hands well after handling the cat

With severe cat allergies, the only solution may be to avoid having a cat in the house at all. For most people though, a combination of different strategies to try to reduce the amount of antigen in the environment will help to successfully control the clinical signs of cat allergy to an acceptable level.

Only your doctor is able to diagnose whether you are allergic to cats, and in severe cases, drugs are available which can help ease the severity of the reactions. Antihistamines are usually the mainstay of treatment for sneezing and itching while an inhaler and even steroids are sometimes required for more severe reactions. Always seek advice from your doctor before using any medications.

Development of ‘hypoallergenic cats’

In 2006, a company in the USA called Allerca Inc introduced what was claimed to be cats that were ‘hypoallergenic’ – in other words a cat that did not produce the protein(s) provoking an allergic response in people. According to the company, they identified cats that produced a variant of Fel d 1 that was sufficiently different not to provoke an allergic response. No accepted scientific data was produced to support this claim, and by 2010 the company had apparently stopped selling these cats. The validity of their claims are still debated, but producing a truly hypoallergenic cat is likely to be extremely difficult as although Fel d 1 and Fel d 4 are the major protein causing an allergy, many others can also be involved. Another area of concern would be the size of the gene pool used during the selective breeding programme to develop these cats – using what might be a very small gene pool may allow other significant problems to arise in these cats.

 

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