Boy vs. Girl. Can You Be Allergic to One Cat Gender and Not the Other?


Cat allergies are quite common, affecting around 10% of the population. They occur when the immune system mistakenly identifies proteins found in cat skin cells or saliva as harmful invaders. This triggers an allergic reaction involving the release of histamines and other chemicals into the bloodstream. Symptoms like sneezing, congestion, itchy eyes, and wheezing can result from exposure to cats or traces of cat allergens left in the environment (Sparkes, 2022). While cat allergies can’t be cured, they can often be managed through medications, environmental changes, and immunotherapy. This article explores whether individuals allergic to cats may react differently to male versus female cats.

What Causes Cat Allergies

Cat allergies are caused by allergens found in cat dander, saliva, and urine. The primary allergen is a protein called Fel d 1, which is produced in cats’ sebaceous glands and skin.1 This protein is very lightweight and can become airborne. When inhaled by a person allergic to cats, it triggers an immune system reaction that leads to allergy symptoms.

Cat saliva also contains allergens. The protein Fel d 1 is present in cat saliva, which can transfer to fur when a cat grooms itself. Another allergen called albumin is found in cat saliva as well. When a cat licks a person, the saliva can cause skin irritation, hives, and wheals in those allergic to cats.2

Finally, cat urine contains allergens too. Fel d 1 proteins are excreted through urine. Litter boxes can be a major source of allergens when particles become airborne from cat urine and feces.1 Therefore, the primary causes of cat allergies are the Fel d 1 protein found in dander, skin, and saliva, as well as other proteins excreted in urine.

Differences Between Male and Female Cats

There are some notable differences between male and female cats. These differences stem from sex hormones, genetics, and behaviors.

Male cats tend to be larger than females, even if they are neutered early on. Male cats continue growing until they are around 18 months old, while female cats reach their full adult size by the time they are 1 year old (Male vs Female Cats: Differences, Pros, and Cons).

Intact male cats are more likely to roam, fight with other cats, and spray urine to mark their territory. Neutering can help curb these behaviors. Female cats tend to stay closer to home and be less territorial over their space (How to Spot the Personality Differences Between Male and Female Cats).

Male cats tend to be more social, playful, and affectionate with humans. Females can be more aloof and independent. However, neutering can minimize these gender differences in personality and behavior (Male vs Female Cats: 4 Key Differences Explained).

While trends exist, every cat has their own unique personality shaped by life experiences, environment, socialization, genetics, and more. Gender is just one factor.

Allergen Levels in Male vs Female Cats

Studies have found that male cats tend to produce higher levels of Fel d 1 allergen than female cats. One study published in the Clinical & Experimental Allergy journal found that male cats produced significantly more Fel d 1 in their skin than neutered males or females (Jalil-Colome, 1996). The researchers concluded that sex hormones likely influence Fel d 1 production.

According to Purina, intact male cats generally have higher allergen levels compared to neutered males and females. Female cats that are not spayed can have increased allergen production when in heat or pregnant. But overall, male cats tend to produce more Fel d 1 allergen than females (Purina).

Other Factors Affecting Allergen Levels

There are some other factors besides gender that can affect the levels of allergens cats produce:

Coat Length: Long-haired cats tend to produce lower levels of Fel d 1 allergen than short-haired cats. The long fur traps more of the allergen so less becomes airborne. However, the longer fur also sheds more dander that contains allergens. So the difference may not be significant.

Shedding: Some cat breeds shed seasonally while others shed year-round. Cats that shed less will release less allergen into the environment overall. However, even low-shedding cats still produce the Fel d 1 protein. (Purina Institute)

Neutering: Neutered male cats tend to roam, scratch, and spray less than intact males. This means they spread less allergen around the home from these behaviors. However, neutering does not directly affect Fel d 1 production. An intact male kept strictly indoors would likely produce similar allergen levels to a neutered male in the same environment.

Managing Allergies with a Cat

There are several ways to manage allergies if you want to live with a cat but suffer from allergic reactions. This involves reducing exposure to allergens and controlling the spread of allergens in your home.

One of the most important steps is to keep cats out of bedrooms, as this is where you spend many hours sleeping and are exposed for long periods. Shut bedroom doors and do not allow cats to sleep on beds (reference:

Regular grooming and bathing of cats can reduce levels of Fel d 1 allergen on their skin and in the air. Aim to brush cats at least once a day and bathe them weekly if possible (reference:

Using high efficiency particulate air (HEPA) filters in heating and cooling systems, vacuums, and stand-alone air purifiers can capture allergens and improve air quality. Change filters regularly according to manufacturer recommendations (reference:

Getting Tested for Cat Allergies

If you suspect you may be allergic to cats, getting tested can help confirm whether cat allergens are triggering your symptoms. Two common allergy tests used are skin prick testing and blood tests checking for IgE antibodies.

Skin prick testing involves pricking the skin with tiny amounts of suspected allergens, including cat dander, saliva, and urine proteins. If a red, itchy bump develops, it indicates an allergy. This test provides rapid results, though accuracy depends on the quality of allergen extracts used.

Blood tests detect IgE antibodies to specific allergens. A sample is drawn and exposed to cat allergens in a lab. Levels of IgE antibodies correlate with allergy severity. Blood tests can assess sensitivity to a wider range of substances. However, skin testing is often preferred for evaluating animal allergies. Labcorp and other labs provide blood-based pet allergy testing.

Allergy testing can identify the specific cat allergens triggering symptoms. This helps determine suitable treatments and precautions. However, testing only detects allergies, not whether male or female cats cause worse reactions.

Treatment Options

There are several treatment options available for people with cat allergies:

Antihistamines like cetirizine (Zyrtec), loratadine (Claritin), or fexofenadine (Allegra) can help relieve allergy symptoms like sneezing and itchy eyes. Antihistamines work by blocking the effects of histamine, which the body releases in response to an allergen. They come in pill and liquid forms. While effective for some, antihistamines may cause side effects like drowsiness. [1]

Allergy shots or immunotherapy involves being given injections of a cat allergen extract over a period of time. The goal is to desensitize the immune system to the allergen. Studies show allergy shots can significantly reduce allergy symptoms and the need for medication in many people. The treatment takes 3-5 years and requires regular injections. [2]

Oral immunotherapy is a newer option that involves placing allergen extracts under the tongue. It works similarly to allergy shots to desensitize the immune system over time. This treatment may allow for at-home administration after the initial doses. More research is still needed on the effectiveness of this method. [1]

Tips for Cat Allergy Sufferers

There are some simple steps cat allergy sufferers can take to help minimize allergy symptoms when living with a cat:

Wash your hands after any contact with cats. Cat allergens are sticky proteins that bind to clothing and skin. Washing your hands removes these allergens and prevents spreading them around your home or to your face where they can trigger allergic reactions. Use soap and warm water and wash for at least 20 seconds (source:

Vacuum frequently using a vacuum with a HEPA filter. Cat allergens accumulate quickly in carpets, fabrics and surfaces around the home. Frequent vacuuming can remove these allergens before they circulate and cause reactions. Focus on areas where your cat sleeps and grooms itself (source:


In summary, it is possible to be allergic to male cats but not female cats. This is because male cats produce a protein called Fel d 1 in their saliva, skin secretions, and urine. Fel d 1 is the major allergen present in cats.

Male cats tend to produce more of this allergen than female cats, especially non-neutered males. So someone who is sensitive to Fel d 1 may react to males but have fewer or no symptoms around females.

However, there are many factors that influence allergen levels in cats. Breed, age, environment, grooming habits, and hormones can all play a role. The only way to know for certain if you are allergic to a specific cat is through allergy testing.

If you have cat allergies, options include medications, allergy shots, air filters, frequent bathing of the cat, and keeping the cat out of the bedroom. Work closely with your allergist to find the best ways to manage symptoms.

In conclusion, it is possible to be allergic to male cats while tolerating females. But every cat and every allergy sufferer is different. With the right precautions and treatment, even allergic people can often enjoy life with their feline companions.

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