Pet allergy - the nightmare of animal lovers

Which animals can cause a pet allergy?

Pet allergies are particularly known in mammals with which many people frequently come into contact.  Pets and farm animals such as cats, dogs, horses, rabbits, or budgerigars are among the animals that can cause allergies.

Since all these animals have dense fur or feathers, it was once assumed that the hair or feathers were responsible for the symptoms. That is why people still often refer to a  pet hair allergy or  feather allergy today. However, hair and feathers primarily act as carriers for the actual allergens that cling to them.

Cats are very popular pets that can unfortunately trigger allergies in many people.  Cat allergy may even be the most frequently diagnosed and treated pet allergy, as cats are widespread and can cause severe symptoms in allergy sufferers, including allergic asthma. Cats produce a protein complex called Fel d 1 - these proteins are found in the cat's saliva and other secretions and trigger cat allergies. During grooming and marking, the allergens get onto the fur and skin. Loose hair and dander bring them into contact with human mucous membranes or airways, where they provoke an immune response. That is why people can also be allergic to hairless cats. The amount of allergens produced is not the same in every cat breed, so some cats trigger cat allergies very frequently while others do so only rarely

Dogs also carry potentially allergy-triggering enzymes in their saliva. In dogs, too, the allergen reaches the hair through grooming, and some breeds have a great deal of hair and shed it in large quantities. Nevertheless, a dog with very thick or long fur is not automatically an “allergy dog.” Just as with cats, the amount of allergens in saliva also varies among dog breeds. Poodles and Yorkshire Terriers, for example, are considered dogs that cause only mild allergic reactions.

Horses have an allergen called Equ c 1. This protein belongs to the lipocalins, which perform functions in the cell metabolism of practically all living organisms. Since they occur in the horse's skin and hair, this is referred to as a “horse hair allergy.” The proteins are also found in horse excrement. Interestingly,  cross-allergies with the proteins in cat and dog saliva are common. People with horse allergies are therefore often also allergic to dogs or cats. However, horse hair allergy is one of the less frequently diagnosed animal hair allergies, because despite the high number of riders in Germany, only a relatively small proportion of the population regularly interacts with horses.

Rabbits and guinea pigs are very popular small pets. Children in particular enjoy cuddling these fluffy animals. However, care should be taken to determine whether children develop allergies to the animals. In rabbits and guinea pigs, the  allergens are found in the urine. Keeping the animals in a clean and hygienic environment and cleaning their enclosure regularly helps ensure that as few allergens as possible get onto the fur and from there onto people.

Mice and rats are bred as pets, but they also come into contact with people as pests in rural and urban environments. The allergens of these rodents are found primarily in their dander and urine. A “Laboratory Animal Allergy” (LAA) caused by laboratory mice is even known, and it frequently affects employees in animal laboratories. The symptoms of a “mouse allergy” resemble classic hay fever, but in the long term they can also progress to allergic asthma.

Birds such as budgerigars or parrots can also cause allergies. Allergens are found in their excretions or salivary glands, from where they get onto the feathers. Mite droppings in the plumage could play another role - however, bird mites are not house dust mites. In addition, ornamental birds kept in hygienic conditions usually do not have mites. Although people often refer to a feather allergy, the feathers are therefore not responsible for the symptoms. However, some bird species have  so-called powder down feathers, which disintegrate into a very fine powder and serve to clean the plumage. This feather dust can cause allergy-like irritation. Allergies could also be triggered by mold or mite droppings in bird food, as well as by substances in bird litter. If a bird allergy is suspected, the accompanying circumstances must therefore be investigated thoroughly to rule out other allergens.

Symptoms and effects of pet allergies

A pet allergy can take years to manifest. It is not unusual for people who have been able to live with cats without problems for a long time to develop a cat allergy. Once a pet allergy exists, it appears as an  immediate-type allergy  - the symptoms therefore occur immediately or within a few minutes of contact with the allergy trigger. The symptoms of different pet allergies are very similar - people who keep dogs, cats, and other animals together therefore only find out which animal is “responsible” after an allergy test. Identifying pet hair allergies can also be made more difficult by the similarity of the symptoms to typical hay fever symptoms.

• Cold-like symptoms such as a runny or blocked nose and frequent sneezing may indicate a pet allergy. Of course, allergic rhinitis or an ordinary cold could also be responsible. On their own, these symptoms are usually not enough to suggest that someone might be allergic to dogs, cats, or other animals.
• Burning, itchy, and watery eyes are a common accompanying symptom of pet allergies. The symptoms often become much worse when the eyes are rubbed - they may then swell, become bright red, and water profusely. Such eye symptoms are common, for example, with a cat allergy. If the problems occur shortly after contact with an animal, they are a clear indication of a possible pet allergy.
• Rashes and hives are relatively rare with pet allergies and are not considered typical symptoms.

If a pet allergy is not recognized and treated or is simply ignored, it is difficult to predict how it will develop. Like other allergies, it may become weaker over time and even almost disappear - a kind of natural hyposensitization takes place. However, the allergy may also become stronger - especially in allergic children, it is warned that continued contact with animal allergens can lead to the development of  allergic asthma . You should therefore seek medical help in any case if you believe that you or your children have a pet allergy.

Diagnosing, treating, and preventing pet allergies

To diagnose a pet allergy, your doctor will first take a medical history. The symptoms of a pet hair allergy can also be caused by other allergies or illnesses. If the suspicion is confirmed that animal allergens are actually behind your symptoms, an  allergy test can provide clarity. The usual procedure is a prick test: allergen-containing liquid is dripped onto the skin, and the skin is scratched through the drop. This allows the allergen to penetrate the upper layer of skin. If you are allergic to the substance being tested, a clear but harmless skin reaction appears. In some cases, blood tests are also performed to detect allergies.

Depending on how severely a pet allergy manifests itself, it may be necessary to avoid contact with the animals concerned. This measure is especially painful for pet owners, but the separation does not have to be permanent. For mild symptoms,  medications for the symptoms may be taken. Often, an allergy also weakens on its own over the course of a person's life - continued contact with the animals could lead to natural desensitization. Since an allergy can also become stronger - caution is particularly advised with children - you should discuss the necessary measures with a doctor.

 Hyposensitization can be carried out in an allergy clinic and can reduce allergy symptoms over a period of several years. Patients receive small doses of the allergen, which are gradually increased over several months to slowly accustom the immune system to the trigger. Good results have been achieved, for example, in people with cat allergies. However, not every pet hair allergy can be treated in this way.

It is uncertain whether pet allergies can be prevented. At least it is certain that avoiding a pet does not protect against an allergy. Even people who have never had a pet or have had little contact with animals can develop a pet allergy. It is even possible that having a pet tends to protect against allergies, because the immune system can become accustomed to the allergens. The cause of an allergy to animal proteins has not yet been scientifically clarified. Pet allergy is therefore a highly individual condition that must always be assessed anew from patient to patient.