Allergy to cats - introduction

A red face, constant sneezing, runny nose, even a skin rash. Either you are coming down with something nasty, or you have a cat allergy. Many people suffer from allergy to cats, and the sad thing is that some of them actually like cats, and would love to have a cat in their house, if only the mere sight of one didn't have them rushing for tissues and an inhaler.

An allergy is your body's response to an 'allergen'. That is, a small foreign body that your system suspects is something nasty. As your body's defences launch an allergic response, it ramps up your production of histamine, a chemical used in fighting disease. It is histamine which largely responsible for allergic symptoms (and for some of the symptoms you get when your body is fighting a real threat).

An allergic reaction causes red, itchy, watery eyes; that annoying nasal congestion; an itchy nose; sneezing; problems with breathing; a chronic sore or scratchy throat ; coughing, wheezing, and itchy skin. Fortunately most sufferers get away with one or two of these symptoms - but still allergies are no joke. The word "allergy" itself comes from the Greek words allos meaning "other" and ergon meaning "work". The expression was coined by an Austrian, Dr Clemens von Pirquet, in 1906. Dr Pirquet noticed that some of his patients had a flu-like response to some apparently innocuous substances such as dust, pollen and certain foods. He called this response an allergy.

Just as with dust, pollen etc, you can also be allergic to animals, and allergy to cats is one of the most common animal allergies (partly because cats are such common animals. You might be allergic to Panda bears and never know it.) However, there are also specific reasons why cats cause some people's bodies to react as they do. Allergy to cats is mostly caused by something called 'Fel d 1' glycoprotein. This is found in cat saliva, material from sebaceous glands in the cat's skin, anal sebaceous glands and from there, on the fur itself. Some people can also be allergic to albumin in a cat's urine, saliva and blood. It is estimated that about a quarter of people who suffer from allergies will be allergic to cats; and cat allergies are responsible for about half of all animal allergies.

Because there is 'Fel d 1' protein in a cat's saliva, cats deposit large amounts of it on their coats when they groom themselves. (And cats groom themselves a lot.) From there, the allergen is spread into the carpets, bed, cushions and around the house in general. Some of it hitches a ride on dust particles and floats through the air until it inevitably ends up in the respiratory system ofthe person in the room with the greatest sensitivity to it. Because this protien also comes from the skin, the common belief that hairless cats are allergen-free cats is unfortunately not true. Short-haired or long-haired, or hairless, a cat will still produce its allergen. But some cats produce more than others. For example Fel d1 production is stimulated by testosterone, so male cats produce more of the stuff than females, and a long-haired, un-neutered tomcat with the right body chemistry can probably raise a rash on a block of granite.

Because of the way that Fel d1 can get tracked about, many people also do not realise is that cat allergens can be present even in places where animals don't go, for example offices, public places or pet-free homes. Dander, (the flakes which a cat sheds from its skin and hair) is very small, about 1/10 the size of pollen, and sticky. Dander can easily get airborne or be transported on the clothes of people with pets at home. If you are allergic to cats and move into a new home, it is worth checking that you have carefully vaccumed up all traces of dander, since the cat may be gone, but the allergens will still be around.

If you suspect that you are allergic to cats, have a look at the checklist below of the most common symptoms.

1. Immediate (acute) response - characterised by rhinoconjunctivitis (flu-like symptoms) and wheezing. This happens within minutes of contact with a cat or being in a home which has cats. If you get this response, you probably know about it already.
2. Delayed response - this happens 3-4 hours after you have been in contact with a cat, or at least with its allergens. The symptoms are likely to persist for a number of weeks. Although it's delayed, you still get an acute response, even if your first reaction to the cat did not seem too bad, and and the clear symptoms of an allergic reaction only come later, when your body has had time to brood over things a bit.
3. Chronic response - this response is a classic response in asthma sufferers and it makes the asthma worse. Very often asthma sufferers don't get an acute response and therefore assume they are not allergic to cats. Instead they blame something else for worsening their condition.
4. Contact Urticaria - this is the skin inflammation commonly called hives; raised, itchy areas of skin that appear in varying shapes and sizes. Hives range from a few millimeters to several inches in diameter and can be round, or form rings or large patches.
5. Worsening of atopic eczema - an itchy inflammation of the skin which causes a dry, red, flaky or scaly rash
6. Allergic rhinitis, perennial - an allergic reaction in the linings of the nose and sinuses. You know you have this if you can't stop sneezing.

By now you are probably wondering whether cats should be classified as Weapons of Mass Destruction. Here's two things that might cheer you up. Firstly, cats can get allergies too, and secondly, there is a lot you can do about it - for yourself and your cat.