Better understanding cat and dog allergies
Cat and dog allergies are allergic reactions to proteins produced by these animals. These allergens are primarily found in the animals’ saliva, urine, and sebaceous glands. Allergies to cats and dogs affect 10–20% of the global population (Chan & Leung, 2018). Such allergies can lead to mild to severe symptoms that impact the daily lives of those affected. But what exactly happens during a cat or dog allergy? This article explains what occurs in the body during such an allergic reaction, how to recognize it, and what can be done about it.
Table of Contents
- What is an allergy?
- What is the difference between contact and inhalant allergies?
- What exactly causes a reaction in a cat or dog allergy?
- What are the causes and risk factors of cat and dog allergies?
- What symptoms can occur with cat and dog allergies?
- What is cross-reactivity?
- Are there hypoallergenic cat or dog breeds?
- How are cat and dog allergies diagnosed?
- How are cat and dog allergies treated?
- Summary
What is an allergy?
An allergy is an oversensitive reaction of the immune system to certain substances that are normally harmless. These substances are called allergens. Common allergies include peanut or latex allergies, but in the case of a cat or dog allergy, the allergens are proteins produced by cats or dogs. The immune system mistakenly identifies these proteins as a threat and triggers defense mechanisms. This leads to the release of histamine and other inflammatory substances in the body, which in turn cause typical allergy symptoms such as sneezing and watery eyes. Ultimately, the cause of this reaction lies in the immune system’s misperception (Mayo Clinic, 2022).
What is the difference between contact and inhalant allergies?
The main difference between the two lies in how the allergic reactions are triggered:
| Inhalant allergies | Contact allergies |
|---|---|
| With inhalant allergies, the body reacts to allergens that become airborne, such as pet hair, dander, or saliva from cats or dogs. These allergens can be inhaled and enter the respiratory tract, where they trigger allergic reactions. | With contact allergies, the allergic reaction occurs when the skin or mucous membranes come into direct contact with allergens, for example when petting or cuddling with a cat or dog. |
Both types of allergies can occur individually or in combination, depending on the body's sensitivity and response to specific allergens.
What exactly causes a reaction in a cat or dog allergy?
Cat allergy
A cat allergy is a reaction of the immune system to specific proteins produced by cats. The main allergen responsible for these reactions is a protein called Fel d 1. This protein is primarily found in the cat’s saliva, urine, and sebaceous glands. When a cat grooms itself, it spreads this protein onto its fur, which can then be dispersed into the environment via the hair. People with a cat allergy can develop severe symptoms upon exposure to these allergens.
Dog allergy
Similar to cat allergies, dog allergies are caused by a specific protein produced by dogs. This protein, known as Can f 1, is mainly found in the dog’s saliva, urine, and sebaceous glands. It is transferred to the dog’s fur during grooming and can then be distributed in the surrounding environment. Individuals with a dog allergy may experience allergic reactions similar to those caused by cats.
Terms like “cat hair allergy” or “dog hair allergy” are misleading, as the reaction is not merely to the fur, but to specific proteins in the animals’ saliva, urine, and sebaceous glands (Chan & Leung, 2018; Cleveland Clinic, 2022).
What are the causes and risk factors of cat and dog allergies?
Various factors can contribute to cat or dog allergies, and the exact mechanisms of allergy development are not yet fully understood. These factors include genetic predisposition and prior exposure to the allergen. However, not everyone who is exposed to an allergen necessarily develops an allergy, and not everyone with a genetic predisposition ends up developing an allergic reaction. Environmental factors such as air pollution, climate, lifestyle, and hygiene practices—as well as existing allergies like hay fever or dust mite allergies—can increase the risk (Salo & Zeldin, 2009).
What symptoms can occur with cat and dog allergies?
Allergies to cats and dogs can trigger a variety of symptoms ranging from mild to severe. These symptoms typically appear shortly after exposure to the allergens and usually subside within a few hours to a few days. However, symptoms may persist with continued exposure. Common symptoms include:
- Sneezing
- Watery or itchy eyes
- Runny or congested nose
- Skin rashes
- Breathing difficulties
- Hives
- Fatigue
- Asthma
Source: Mayo Clinic, 2021
Long-term allergy symptoms from cat and dog allergies can be marked by persistent inflammation of the airways, leading to chronic coughing, breathing problems, as well as skin issues like eczema and rashes, along with exhaustion (Mayo Clinic, 2021).
Want to get an overview yourself?
If these symptoms sound familiar or you simply want to be sure whether you have an allergy, the Homed-IQ allergy test offers a solution. With this Extensive Allergy Test, your blood can be tested for 295 allergens (including cat and dog allergens), providing a detailed overview of your sensitivities, including possible cross-reactivities.
What is cross-reactivity?
Cross-reactions occur when the immune system reacts to similar allergens that resemble the original allergen. In the case of cat and dog allergies, this means that people allergic to one of these animals may also react to other allergens with similar proteins. Cross-reactivity between cat and dog allergens is complex, but there is evidence of shared allergenic components between the two animals. This expands the range of potential triggers and is important for the diagnosis and treatment of allergies (Reininger et al., 2007).
Are there hypoallergenic cat or dog breeds?
Yes, there are some cat and dog breeds that are considered hypoallergenic or produce fewer allergens than others. These breeds may be more suitable for individuals with allergies. However, it is important to note that no cat or dog breed is completely free of allergens, and individual reactions can vary greatly. Before getting a pet, it is advisable to take an allergy test and spend time with the specific breed to assess personal tolerance (Nicholas et al., 2011; ACAAI, 2018).
How is a cat or dog allergy diagnosed?
The diagnosis of a cat or dog allergy is usually based on a combination of clinical examinations, allergy testing, and medical history. The history includes questions about symptoms, their progression, and possible triggers. Common methods used to identify a cat or dog allergy include:
- Skin test (prick test): In this test, small amounts of cat or dog allergens are introduced into the skin. If redness, swelling, or itching occurs at the site, it may indicate an allergy.
- Blood test (RAST test): The Radioallergosorbent Test (RAST) is a laboratory blood test used to measure the levels of specific IgE antibodies in the blood. IgE antibodies are associated with “true” allergic reactions and indicate sensitivities to specific allergens.
- Elimination trial: By avoiding contact with cats or dogs for a period of time, you can observe whether symptoms improve. If symptoms worsen upon re-exposure, it is a strong indication of an allergy.
Source: NHS, 2022
How are cat and dog allergies treated?
The treatment of cat and dog allergies includes various approaches to relieve symptoms and minimize contact with allergens.
What medical options are available for cat and dog allergies?
- Medication: Symptom relief methods include antihistamines, nasal corticosteroids, decongestants, and special eye drops that can help alleviate symptoms such as itching, nasal congestion, and watery eyes.
- Immunotherapy: Also known as desensitization or allergy shots, this is a long-term treatment option for people with cat and dog allergies. The goal is to increase the body’s tolerance to the specific allergens that trigger allergic reactions. This is done by gradually exposing the body to increasing doses of these allergens. This treatment requires regular medical supervision (Virtanen, 2018).
- Emergency medication: Epinephrine auto-injectors are important for individuals who experience severe allergic reactions. They provide immediate relief in life-threatening situations such as anaphylactic reactions. These medications should be used under medical guidance and checked regularly to ensure their effectiveness.
Source: Cleveland Clinic, 2022
What options are there to minimize contact with allergens?
To reduce contact with allergens, it is advisable to assess which measures are personally helpful. The following tips may support you:
- Keep animals out of bedrooms and living rooms
- Use a HEPA air filter
- Wash your hands after contact with animals
- Avoid touching your eyes, nose, or mouth after contact with animals
- Use allergen-proof bedding and pillow covers
- Vacuum and air out your home regularly
Source: Mayo Clinic, 2021
Summary
Cat and dog allergies are immune reactions to proteins produced by these animals and affect 10–20% of the global population. They can lead to symptoms such as sneezing, watery eyes, and skin rashes, which can impact daily life. Diagnosis is based on clinical examinations and allergy testing, while treatment includes medications, immunotherapy, and emergency medication. To minimize allergen exposure, individual strategies such as regular vacuuming, using air filters, and restricting pet access can be helpful.
