Animal allergy

Allergies to cats, dogs, horses and rodents are common and may cause allergy symptoms throughout the year.

A young cat peeping through a window

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

In Switzerland, most cases involve sensitisation to cats, dogs, horses and rodents. Allergic reactions to cats are more common than to dogs, although the reasons for this are unclear. Cat allergies of varying severity occur with all breeds of cat. The main allergens are found in the saliva, tears, urine and dead skin cells and are spread by the cat licking its fur, which is why people mistakenly talk of an allergy to animal fur. Female cats and castrated males secrete fewer allergens than non-castrated tomcats. However, most people also react to castrated tomcats and females. The main allergen from dogs is predominantly found in the fur and saliva. The allergenic burden for sufferers varies, depending on the breed of cat or dog. Generally speaking, short-haired dogs are known to produce more allergens than long-haired ones. To date, there is no clear evidence that any particular breed of dog, cat or horse produces either no or very few allergens (i.e. is hypoallergenic) and can therefore be recommended for allergy sufferers.

Allergens from house pets, like other airborne allergens as well, bind to dust particles and, depending on the size, 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 animals are not normally found. This explains why high levels of animal allergens can be detected, for example, in classrooms and hotel rooms, in cinemas and on public transport. This means that people can have an allergic reaction without any animal actually being present.

Symptoms

Allergy symptoms can manifest as follows: runny nose, conjunctivitis, and severe 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

It often happens that a pet allergy is only identified after the pet has been adopted.

The following measures can help reduce the allergenic burden in the immediate environment:

  • Limit the pet’s access to your home; keep the pet outside the home, where possible.
  • Do not let the pet into sleeping areas.
  • Wash your hands after any contact with your pet.
  • Clean clothes with a clothes roller (do not use clothes brushes).
  • Have other members of the family clean the areas where the pet rests and feeds.
  • Use washable covers for upholstered furniture and seating.
  • Remove carpets and other "dust traps".
  • Vacuum clean regularly: use a cleaner with HEPA filter level 11 and allergen-proof casing.
  • Wet mop floors on a daily basis.
  • Use an air purifier with HEPA filter level 11.

Despite these measures, the trigger for the symptoms, namely the animal allergen, is still present. Animal hairs spread throughout the home and adhere to clothing and other textiles. Animal allergens are still present in the home even weeks after the pet has gone.

Before acquiring a furred or feathered animal, allergy sufferers should consider a possible animal allergy with all its consequences (long-term treatment or having to give away the beloved pet).

Facts and figures

If someone suffers from asthma, they are advised against having a furred or feathered pet. Animals generally cause more dirt and dust in the home, which can have an adverse effect on the breathing of asthma sufferers. Animal hairs in themselves are an added irritation to the airways.

Given the current state of knowledge, it can neither be proved nor ruled out that growing up with a pet can have a protective effect against developing allergies.

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