Why do I get asthma, rhinitis or itching when I get close to a cat?

These symptoms are the result of an immunological reaction to specific proteins (primarily Fel d 1) found in the animal’s saliva, skin, and urine, rather than its hair.

Unlike other allergens, this protein is microscopic and aerodynamic: it remains suspended in the air for hours or even days after cleaning. This explains why you may suffer a severe asthma attack simply by entering a room where a cat lives, even if the animal is not present. Many patients suffer severe symptoms while mistakenly believing that “cleaning more” will solve the problem.

My objective in the consultation is threefold:

1. MOLECULAR DIAGNOSIS (The Key): A positive skin prick test is not enough. We need to determine through molecular analysis whether you are allergic to the primary protein (Fel d 1) or others (albumins). This is critical: vaccines have high success rates for Fel d 1 but low efficacy for other proteins. Without this data, treatment is a gamble.
2. INFLAMMATION CONTROL: The immediate goal is to halt the bronchial and nasal reaction using latest-generation drugs that do not cause drowsiness, allowing you to visit homes with cats or live with your own while minimizing the risk of an asthma attack.
3. CURATIVE TREATMENT (Immunotherapy): If the molecular diagnosis allows it, we will design a Specific Immunotherapy (Vaccine). This is the only treatment capable of generating long-term immunological tolerance, reducing the need for medication and increasing the chances of keeping your pet.

Specialized Treatment: Science vs. Home Remedies

The medical solution is not always “getting the cat out of the house.” My clinical approach is based on scientific evidence and precision medicine:

1. Component-Resolved Diagnosis (Microarrays)

We use advanced technology to break down your allergy. Differentiating whether you react to Fel d 1 (uteroglobin) or to Fel d 2 (albumin) is vital. Albumin, for example, is present in other animals and foods (pork-cat syndrome), which radically changes the treatment and the precautions you must take.

2. Immunotherapy (Allergy Vaccines)

It is the most powerful tool we have. The progressive administration of the allergen allows the immune system to “get used” to the cat’s presence. It is specifically indicated for patients who live with animals or veterinary professionals, always following a feasibility study.

3. Experience and Research

As a specialist, I have conducted specific research on indirect exposure to cat allergens and nasal response. This knowledge allows me to fine-tune the diagnosis in complex cases where conventional tests do not explain the severity of symptoms.

• Reference: Role of nasal challenge and local eosinophilia (Eur Ann Allergy Clin Immunol)

Beyond Skin Prick Tests: Molecular Diagnosis (Fel d 1 vs. Albumin)

In our practice, diagnosing cat allergy is not limited to a positive skin prick test result. To determine the true prognosis and the viability of immunotherapy treatment, it is essential to decipher exactly which specific protein of the animal your immune system is reacting to. Not all “cat allergic” patients are the same.

Fel d 1 (Uteroglobin): The Marker of Genuine Allergy

This is the major allergen, specific to cats and responsible for sensitization in over 80-90% of patients.

• Clinical Significance: If you are sensitized primarily to this component, your symptoms are specifically caused by the cat.
• Prognosis: This profile usually responds favorably to specific immunotherapy (allergy shots), as high-quality commercial extracts are standardized based on Fel d 1 concentration. This opens a real door to the possibility of living with the pet.

Fel d 2 (Serum Albumin): The Risk of Cross-Reactivity

This is a minor allergen and a protein present in the blood of many mammals, not just cats.

• Clinical Significance: Sensitization to this component may indicate that your allergy is not exclusive to cats, but that you could also react to dogs or other animals (cross-reactivity). In rare cases, it can be associated with pork-cat syndrome (allergic reaction after eating pork).
• Prognosis: Clinical management is more complex, and the response to standard cat vaccines may vary. Precise molecular diagnosis allows us to identify this risk and adjust treatment expectations before starting.

Molecular Phenotypes in Cat Allergy: Prognostic Implications (Fel d 1 vs. Fel d 2)

Precision allergology diagnosis should not be limited to skin prick test positivity. Scientific evidence demonstrates significant heterogeneity in patients’ sensitization profiles, which directly impacts immunotherapy outcomes.

Fel d 1 (Uteroglobin): The Marker of Genuine Allergy

This is the major allergen (secretoglobin), responsible for sensitization in 90-96% of cat-allergic patients ^[1].

• Clinical Significance: Indicates primary and specific sensitization to Felis domesticus.
• Prognosis: This phenotype shows a favorable response rate to specific immunotherapy (70-80% symptom reduction) ^[2], as high-quality standardized extracts are quantified based on this major allergen.

Fel d 2 (Serum Albumin): The Cross-Reactivity Marker

A minor allergen present in 14-23% of sensitized patients ^[3]. As a highly conserved serum protein, it shares homology with albumins from other mammals.

• Clinical Significance: Suggests a profile of polysensitization or cross-reactivity. It is the marker responsible for Pork-Cat Syndrome, a hypersensitivity reaction following the ingestion of undercooked pork ^[4].
• Prognosis: Clinical management requires caution. Response to conventional vaccines may be suboptimal, and it necessitates ruling out associated food allergies.

References:
[1] Bonnet B, et al. Allergy Asthma Clin Immunol. 2018.
[2] Nwaru BI, et al. Systematic Review. 2019.
[3] Posthumus J, et al. J Allergy Clin Immunol. 2013.
[4] Drouet M, et al. Pork-cat syndrome. 1994.

Common Myths and Errors

Misinformation regarding pet allergies is abundant and dangerous for respiratory health:

• “The hypoallergenic cat”: There is no such thing as a zero-allergen cat. Some breeds produce less protein, but they can still cause severe asthma in highly sensitive patients. Individual assessment is required.
• “I only have an allergy if I touch it”: False. Cat protein floats in the air and adheres to clothing. You can suffer a severe asthma attack just by entering a room where a cat lives, even if the animal is not present.
• Topical products (Lotions): Although they can slightly reduce the environmental load, they never replace the patient’s medical treatment. Relying on a lotion for the animal for your respiratory health is an unnecessary risk.

Researcher’s Note: Scientific Evidence

I recently published a study analyzing technical details for the accurate diagnosis of cat allergy, based on patient data from the Middle East (Kuwait). These findings help us better differentiate between an allergic patient and one who is simply sensitized.

See study on PubMed (NIH): Cat sensitization vs Allergy

Environmental Measures: My honest opinion

If we decide the cat remains at home, we must be realistic:

• Bathing the cat: Doing so 2 or 3 times a week reduces the protein load on its fur. It is a cost-effective measure.
• HEPA Filters: In older studies, these reduced airborne proteins but did not significantly improve patient symptoms. Modern filters seem to offer better results, but evidence remains contradictory. Personally, I only recommend them for severe patients or where the financial cost is not an issue.

Do you want to keep your pet safely?

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Medical Details for the Informed Patient

Epidemiology and protein behavior

Cat allergy is a frequent disease, affecting between 10% and 20% of the world’s population. Although many cases are mild, its most frequent manifestation is in the form of rhinoconjunctivitis (itching, sneezing, congestion) and asthma.

The protein responsible for 96% of cases, Fel d 1, is mainly produced in the sebaceous glands of the skin and accumulates in the fur. This protein has a unique ability to “fly” inside the room. Therefore, even if the cat is playing on the floor, it can cause severe symptoms in an allergic patient who is simply sitting at a table, as the particles remain in suspension.

Does early exposure prevent allergy?

Until a few years ago, there was a theory that the more a patient is exposed to a cat, the higher the risk. However, recent studies have shown that reality is more complex.

Evidence has been published (see study) suggesting that exposure to dogs during childhood decreases the possibility of being allergic in adulthood. Unfortunately, results with cats are less clear, although my personal clinical opinion based on practice is that future studies could demonstrate a similar effect. What we do know is that intermittent contact (not continuous) in adulthood increases the risk of sensitization.

Researcher’s Note: I recently published a study (see on PubMed) analyzing technical details for the accurate diagnosis of cat allergy, based on patient data from the Middle East (Kuwait). These findings help us better differentiate between an allergic patient and one who is simply sensitized.

Scientific Evidence and Clinical Experience

Featured Research: I recently published a technical study analyzing patient data in the Middle East (Kuwait) to improve diagnostic precision. This work helps the scientific community correctly differentiate between an allergic patient and a simply sensitized, asymptomatic one.

See publication on PubMed (NIH)

Impact of the Fel d 1 protein

Cat allergy affects between 10% and 20% of the world’s population. The protein responsible for 96% of cases is “Fel d 1”, which is mainly produced in the skin glands and has the capacity to remain suspended in the air. This explains why symptoms can develop even in places where the cat was present days or months ago.

It is interesting to note that while early exposure to dogs seems to decrease allergy in adulthood, the results for cats are less clear. My professional opinion, based on daily clinical practice, is that future studies will demonstrate similar protective effects if exposure is continuous from childhood.