Animal allergy

Domestic animals have lived alongside mankind for millennia. Whereas in the past they mainly served as farm animals and were used for work and hunting, nowadays they are usually looked on as part of the family or as a cherished companion. The closer contact with them also increases the risk of developing an allergy to them.

Triggers

Most cases of sensitisation involve cats, dogs, horses and rodents. Allergic reactions to cats are more common than to dogs, though why this should be the case is still unclear. Cat allergens are present, to varying degrees, in all breeds of cat. Allergens are primarily found in dander (skin flakes), saliva, hair, urine and tears. When cats lick themselves, they spread the allergens on their fur, which is why the allergy is also often known as pet dander allergy. Female cats and castrated tomcats produce fewer allergens, but sufferers still have a reaction to them. The main dog allergens are primarily found in the fur and saliva. The allergenic burden varies between breeds. In general, short-haired dogs are known to produce more allergens than long-haired dogs. To date, there is no evidence that any particular breed of dog, cat or horse is clearly hypoallergenic and thus can be recommended for allergy sufferers.

To date, there is no evidence either way that growing up with a pet helps protect against an allergy to the pet.

Allergens in the environment

Like other airborne (aerogenic) allergens, allergens from pets bind to dust particles and, depending on the size of the particle, float around in the air for hours until they settle on the ground. Because animal allergens adhere to people’s hair and clothing, they can be transferred to the air in places where no animals are normally found at all. This explains why high levels of animal allergens can be detected, for example, in classrooms and hotel rooms, in cinemas and on public transport. Sensitive people can thus have an allergic reaction without any animal previously or actually being present.

Cross allergies

In a few cases, an allergy to cats can lead to a cross allergy to pork or foods containing pork (pork-cat syndrome). Fortunately, this form of secondary allergic reaction is rare. Cross-reactions between animals such as dogs and horses are more common.

Symptoms

Allergy symptoms can manifest as follows: runny nose, conjunctivitis, and allergic asthma. A shock reaction may even occur in isolated cases. Scratches from cats and dogs can lead to allergic skin irritation and swelling.

Diagnosis

Anyone who suspects they may be allergic to an animal, based on their own observations, can have this investigated by a doctor, who will take a detailed medical history and arrange for a skin and blood test.

Treatment

First of all, it is essential to avoid any further contact with the allergen. In the case of an animal allergy, this means no longer having any contact with the animal. Giving up a cherished pet or no longer riding a horse, however, is easier said than done. There are a few measures that can be taken by those who find it very hard to give up their pet (see Tips and tricks).

Medication such as anithistamines or corticosteroids can help alleviate the symptoms.

Allergen-specific immunotherapy or desensitisation should only be considered for sufferers with an allergy to cats, dogs or horses where moderate to severe symptoms persist despite all the measures and medication taken. For the best possible result, the animal should ideally be relocated or given away prior to therapy.

Tips and tricks

As with all allergies, the most effective treatment is to avoid the allergen/contact with the pet/animal. If it is not possible to keep the pet in a separate area, certain measures should be taken to reduce the allergenic burden in the immediate environment:

• keep the pet outside the home, where possible
• limit the pet’s access to the home
• do not let the pet into sleeping areas
• wash hands after any contact with the pet
• clean clothes with a clothes roller (do not use clothes brushes)
• let other people who are not allergic clean the areas where the pet rests and feeds
• use washable covers for chairs and cushions
• remove carpets and other dust traps
• wet mop floors on a daily basis
• vacuum clean regularly with a vacuum cleaner fitted with an anti-allergen HEPA filter
• use an air purifier fitted with a HEPA filter.
• When shopping, look out for products with the Allergy Seal of Quality, these are particularly suitable for people with allergies and intolerances and are recommended by aha! Swiss Allergy Centre.

Despite all these measures, the trigger for the symptoms, namely the animal allergens, may still be present over a prolonged period, as animal hairs that adhere to clothing and other textiles will have spread throughout the home. Despite the hygiene measures taken, allergens may therefore still be present in the home from six weeks to several months after the pet has been given away.

Facts and figures

Unfortunately, we have no figures on the number of people who actually have an animal allergy and therefore experience symptoms. However, we do know how many people in Switzerland are sensitised, i.e. are predisposed to develop an allergy after repeated contact with the allergen.

Allergies

Before acquiring a furred or feathered animal, people who are already allergic to pollen, house dust mites or foods should consider that they may also develop an animal allergy, with all its consequences, i.e. long-term treatment or, if an animal has already been acquired, having to give it away.

Atopic eczema

If someone in the family suffers from atopic eczema, they may also develop an animal allergy. Furthermore, the animal may itself be a trigger for atopic eczema.

Asthma

Acquiring a feathered or furred animal is not recommended for anyone with asthma, even if they are not allergic to animals. Pets generally bring more dirt and dust into the home, which can adversely affect lung function in asthma sufferers. Animal hairs also irritate the airways and can aggravate asthma. For allergy sufferers, animals such as fish, tortoises etc are preferable to dogs and cats as pets.

Editors: aha! Swiss Allergy Centre in co-operation with the Scientific Advisory Board. For prevalence figures, see source references.