Dog allergy. What symptoms does it give?
The main symptoms of a dog allergy are rhinitis and sneezing, but conjunctivitis, contact urticaria and even asthma attacks can also occur. Symptoms usually appear after contact with the allergen. However, they do not necessarily result from direct contact with the animal. Allergens, i.e. particles that cause an allergic reaction, persist in the environment even when the dog is no longer present. They can also be transferred on clothes [1,2,3].
What should you do if you notice symptoms of a dog allergy?
First and foremost, you should visit an allergologist. The specialist will decide on the further course of action on the basis of a detailed interview with the patient. Standard tests that help detect an allergy are spot skin tests and the determination of E antibodies against dog allergens. In addition, if the patient has asthma symptoms, spirometry should be performed. This will allow a reliable assessment of the patient’s condition [4].
Skin spot tests involve inserting a small amount of an allergen under the patient’s skin and observing whether a blister appears, which indicates an immune defence response. For the test result to be correct, the patient should discontinue antihistamines at least seven days before the test [5].
In contrast, the determination of specific antibodies E (sIgE) to a given allergen is performed by taking a sample of the patient’s blood. The presence of antibodies directed against a specific allergen, in this case a dog allergen, may be indicative of allergy [5]. In addition, it is worth performing molecular diagnostics.
Molecules are the proteins that are responsible for the onset of allergy. They are the ones that trigger an overreaction of the immune system of the patient in question [5].
Dog allergy – the main culprits
At the moment, 8 proteins responsible for dog allergy have been studied [6]. Patients may be sensitised to one or more of them. However, sensitisation to each molecule may cause different consequences for people with dog allergy [4].
Can f 1
Can f 1 is the earliest discovered allergy-causing molecule in dogs. It is found in their epidermis, epithelium and saliva [7]. It is responsible for up to 75% of all allergies to these animals. It is also thermostable [4], meaning that it is difficult to break down even when washing clothes at high temperatures. There is a possibility of cross-reactivity with the cat molecule Fel d 7 [8].
Can f 5
Can f 5 is a substance belonging to the kallikreins, secreted by the prostate gland of dogs [4]. It is only produced by males. Individuals allergic only to this substance may therefore own a female dog, and such patients account for approximately 30% of all allergies to these animals. Calicrein is responsible for about 70% of all dog allergies [4], also in cases of sensitisation to more than one molecule. Furthermore, hypersensitivity to Can f 5 increases the risk of asthma more than sevenfold by the age of 19 [8].
Can f 2
Another allergenic protein, Can f 2, causes allergy in 30% of all patients sensitised to dogs [8]. It is found in the saliva and epidermis of these animals [7]. Importantly, it is recognised as a marker of asthma severity. Often, hypersensitivity to Can f 2 occurs in association with this condition [7].
Can f 3
Can f 3 is a dog serum albumin that is found in the dog’s plasma, saliva and epidermis. It is produced in the liver and salivary glands [7,4]. It causes allergy in about 27% of those allergic to dogs. It can also cross-react with molecules from other fur-bearing animals, e.g. cat, horse, mouse [4,8]. Even the risk of anaphylactic shock after ingestion of poorly fried or undercooked horse meat has been reported [8]. It is also possible to test positive for Can f 3 as the only one of the canine allergens. Such a result will be due to a primary allergy to Bos d 6 (bovine serum albumin) [4,8]. Proteins from the serum albumin group, and thus also Can f 3, are not very resistant to heat treatment [8].
Can f 4
A protein that is a marker of primary sensitisation to dogs is Can f 4. It causes allergy in about 35% of all those sensitised to these animals [8]. It is also susceptible to heat, whereby Can f 4 can lose its ability to cause allergic symptoms [4]. It is found in the saliva and epidermis of dogs [7].
Can f 6
Can f 6 molecule can also cause allergy to dogs. This substance is responsible for symptoms in about 38% of people with dog allergy. Its potential ability to cross-react with cat and horse molecules has also been demonstrated.
Can an allergy sufferer own a dog?
Dog allergy is a difficult and complex problem. Especially when it only becomes apparent after the animal has been taken in. Obviously, the best thing to do in such a situation is to get rid of it from the surroundings of the sufferer. It has been proven that high allergen concentrations in the home can contribute to more severe allergy symptoms in patients [9]. There are also ways to minimise the presence of dog allergens in the environment.
As allergens are not only found on the dog, but are also transferred with its fur, they can be detected, for example, in dust samples or carpets [10]. For this reason, it is best to avoid objects in an allergic person’s home that easily accumulate dust and dog hair: carpets, curtains, drapes, etc. It is worth noting that, as allergy-causing molecules are found in the epidermis and body fluids of dogs [4], also non-dander breeds are not completely safe for allergy sufferers.
People who are allergic to dogs are exposed to allergens even in public spaces [10]. Sensitising proteins are transferred on the clothes of pet owners and thus reach schools, public transport or the waiting rooms of doctors’ surgeries [4]. Fortunately, there are various ways to treat allergies, both symptomatic and to combat the cause [10]. However, their selection is always decided by an allergologist.
