Allergy to cats

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Allergies to cats are one of the most common allergies among human individuals. Among the eight known cat allergens, the most prominent allergen is secretoglobin Fel d 1, which is produced in the anal glands, salivary glands, and, mainly, in sebaceous glands of cats, and is ubiquitous in the United States, even in households without cats. [1] The second most common is Fel d 2, this type is triggered by the cats dead skin flakes (dander) that are floating in the air as well as in the smell of cat urine. [2] [3]

Contents

Allergic symptoms associated with cats include coughing, wheezing, chest tightening, itching, nasal congestion, rash, watery eyes, sneezing, chapped lips, and similar symptoms. In worst-case scenarios, allergies to cats can develop into severe respiratory symptoms such as rhinitis and mild to severe forms of asthma. [1] Despite these symptoms, there are many types of solutions to mitigate the allergic effects of cats, including medications, vaccines, and home remedies. Hypoallergenic cats are another solution for individuals who want pets without the allergic consequences. Furthermore, prospective pet owners can reduce allergic reactions by selecting female cats, which are associated with lower allergen production.

Cat allergens

Skin prick testing for common allergens such as cat, dust mite, egg, milk, and peanut. A raised bump with redness around, also known as a wheal and flare, indicates an allergic reaction. Skin prick testing for allergies.jpg
Skin prick testing for common allergens such as cat, dust mite, egg, milk, and peanut. A raised bump with redness around, also known as a wheal and flare, indicates an allergic reaction.

Eight cat allergens have been recognized by the World Health Organization/International Union of Immunological Societies (WHO/IUIS) Allergen Nomenclature Sub‐Committee. Fel d 1 is the most prominent cat allergen, accounting for 96% of human cat allergies. [4] The remaining cat allergens are Fel d 2–8, [5] with Fel d 4, a major urinary protein found in the saliva of cats, [6] occurring the most in humans among the other seven allergens. All cats produce Fel d 1, including hypoallergenic cats. The main method of transmission is through a cat's saliva or dander, which adheres to clothing. A 2004 study found that 63% of people allergic to cats had antibodies against Fel d 4. [6]

Fel d 1

Fel d 1 is the most dominant cat allergen. It is part of the secretoglobulin family, which are proteins found only in mammals and birds. Fel d 1 is primarily secreted through the sebaceous glands and can be found on the skin and fur of a cat. It is less commonly secreted through the salivary glands, lacrimal glands, and skin and anal glands. [7]

Fel d 4 and Fel d 7

Fel d 4 and Fel d 7 are cat lipocalins. Fel d 4 and Fel d 7 are two of the most common cat allergens after Fel d 1. Fel d 4 is produced in the submandibular salivary glands and is secreted in the saliva of cats, via which it is deposited on to cat dander during grooming, [6] and is associated with atopic dermatitis in children with cat allergies. [7]

Symptoms

Allergic symptoms to cat dander might include: swollen, red, itchy, and watery eyes; nasal congestion, itchy nose, sneezing, fever, hives, rash, or itchy skin. Swollen Eyelid Due to Allergy (48140096766).jpg
Allergic symptoms to cat dander might include: swollen, red, itchy, and watery eyes; nasal congestion, itchy nose, sneezing, fever, hives, rash, or itchy skin.

Symptoms of an allergic reaction to cats range from mild to severe, and include: swollen, red, itchy, and watery eyes (allergic conjunctivitis); nasal congestion, itchy nose, sneezing (allergic rhinitis or "hay fever"); ear pain similar to pain caused by an ear infection; sore throat or itchy throat; coughing and wheezing; [8] hives or rash on the face or chest; and itchy skin. If a cat has scratched, licked, or bitten someone who is allergic to cats, redness and sometimes even swelling of the affected area will occur. For those severely allergic, symptoms may include airway swelling such as in anaphylaxis, thereby requiring urgent medical attention. [9] [10]

Depending on the person, an allergic reaction to cats can trigger other underlying disorders, such as asthma or atopic dermatitis (eczema).

Pathophysiology

As the allergen enters through the nose or mouth, antigen presenting cells of the innate immune system analyze the allergen and present antigenic peptides to helper T cells. [4] The helper T cells acquire a type 2 phenotype (Th2) and stimulate plasma cells to produce IgE due to the presence of specific cytokines. If Th2 is expressed too much, the symptoms of cat allergies appear. Inhaled cat allergens will activate mast cells, causing coughing, increased mucous production, and airway constriction.

Treatments

Medications

Cat allergies can often be controlled with over the counter or prescription medications. Antihistamines and decongestants may provide allergy relief. [9]

Immunotherapy injections

Some people with allergies find relief in allergen immunotherapy, a periodic injection therapy designed to suppress the body's natural immune responses to the cat allergens. [11] [12] In its early stages, AIT utilized cat dander extract, which consists of microscopic dry skin flakes of cats, but later resorted to Fel d 1 due to issues of standardization. One way researchers use Fel d 1 in immunotherapy is through the alteration of its chemical structure. Disulfide bonds between Fel d 1 chains were broken to reduce the binding between the allergen and immunoglobulin E (IgE), inhibiting an allergic response. [1]

Air Purifiers

Air purifiers are used in many places, for helping subdue cat allergies it is highly recommended. The purifiers catch viruses, dirt, and in this case most important, cat dander and dust. The most common is the HEPA filters that cleanse the air. These filters are also the same ones used in planes to circulate air better. [13]

Cat bathing

Regularly bathing a cat may remove significant amounts of allergens from fur. [14] After bathing, the levels of Fel d 1 on cat skin and fur return within two days of bathing. In addition, amounts of Fel d 1 in the surrounding air return after a 24-hour period of bathing the cat. [1] Feeding the cat a high-quality diet with plenty of omega-3 fatty acids will help keep the coat healthy and minimize dander. [9]

Development of other treatments

Development of several human vaccines have been abandoned, including Allervax [15] and Cat-SPIRE. [16] As of 2019, the Swiss company HypoPet AG is developing a vaccine it hopes could be administered to cats to reduce the emission of Fel d 1 proteins. [17] More recently, in 2022 at the National Institute of Health they conducted an experiment with allergy shots and a monoclonal antibody Tezepelumab. Among the tests, the participants given the shot with the Tezepelumab had greater results than the placebo group and the single allergy shot. [18]

Specialized cat food

Cat food containing the anti-Fel d 1 IgY antibody found in eggs has been found to reduce Fel d 1 levels in fur. [19]

Hypoallergenic cats

A hypoallergenic cat is a cat that is less likely to provoke an allergic reaction in humans. Although the topic is controversial, owners' experiences and clinical studies suggest that Siberian cats, Devon Rex and Cornish Rex cats, Abyssinian cats, Balinese cats, and several other breeds, especially females, are likely to have low levels of Fel d 1, the main allergenic protein. [20] [21]

The Balinese cat is one example of a hypoallergenic cat because it produces little amounts of the allergen Old-Style Balinese Cat.png
The Balinese cat is one example of a hypoallergenic cat because it produces little amounts of the allergen

From among the above cats noted, the most popular cat breeds to be renowned for their hypoallergenic quality are the Siberian and Balinese. These cats produce much fewer protein allergens in comparison to regular domestic household cats or other cat breeds. Cats that have some Balinese ancestry might produce lower amounts of protein allergens. [22] Cat breeds that often have some Balinese lineage include the Oriental Shorthair, Oriental Longhair, and some Siamese cats.

The common theory among these two hypoallergenic medium- to long-haired cat breeds is that their long-haired gene is associated with producing reduced amounts of allergens. This may be the case as the Balinese cat, a medium to long-haired cat breed (also referred to as the Long-haired Siamese cat) is regarded as hypoallergenic, whereas the Siamese cat, a short-haired breed, is not. Some Siamese cats might possess hypoallergenic qualities if they have Balinese ancestry. This might provide some evidence that the long-haired genes or traits within this cat breed have resulted in a cat that can genetically produce less amounts of the cat allergens. [23]

In 2006, the Allerca company announced the successful breeding of a line of hypoallergenic cats. However, no peer-reviewed studies have been done to confirm their claims and many scientists and consumers are skeptical of the company's assertions. [24] The company announced that on 1 January 2010, they will cease their breeding activities. [25]

In 2006, another company, Felix Pets, also claimed to be developing a breed of hypoallergenic cat. [26] [ needs update ]

Cat sex and color

Female cats (unspayed or spayed) produce a lower level of allergens than males, and neutered males produce a lower level of allergens than unneutered males. [27] In 2000, researchers at the Long Island College Hospital found that cat owners with dark-colored cats were more likely to report allergy symptoms than those with light-colored cats. [28] [29] A later study by the Wellington Asthma Research Group found that fur color had no effect on how much allergen a cat produced. [30] [31]

See also

Related Research Articles

<span class="mw-page-title-main">Allergy</span> Immune system response to a substance that most people tolerate well

Allergies, also known as allergic diseases, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic dermatitis, allergic asthma, and anaphylaxis. Symptoms may include red eyes, an itchy rash, sneezing, coughing, a runny nose, shortness of breath, or swelling. Note that food intolerances and food poisoning are separate conditions.

An allergen is a type of antigen that produces an abnormally vigorous immune response in which the immune system fights off a perceived threat that would otherwise be harmless to the body. Such reactions are called allergies.

<span class="mw-page-title-main">Anaphylaxis</span> Life-threatening allergic reaction

Anaphylaxis is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of use of emergency medication on site. It typically causes more than one of the following: an itchy rash, throat closing due to swelling that can obstruct or stop breathing; severe tongue swelling that can also interfere with or stop breathing; shortness of breath, vomiting, lightheadedness, loss of consciousness, low blood pressure, and medical shock. These symptoms typically start in minutes to hours and then increase very rapidly to life-threatening levels. Urgent medical treatment is required to prevent serious harm and death, even if the patient has used an epipen or has taken other medications in response, and even if symptoms appear to be improving.

Hypoallergenic, meaning "below average" or "slightly" allergenic, is a term meaning that something causes fewer allergic reactions. The term was first used in 1953 in an advertising campaign for cosmetics or perhaps as early as 1940. A 2017 study of the top-selling skin moisturizers from Amazon, Target, and Walmart found 83% of those marketed as "hypoallergenic" contained at least one potentially allergenic chemical.

<span class="mw-page-title-main">Allergic rhinitis</span> Nasal inflammation due to allergens in the air

Allergic rhinitis, of which the seasonal type is called hay fever, is a type of inflammation in the nose that occurs when the immune system overreacts to allergens in the air. Signs and symptoms include a runny or stuffy nose, sneezing, red, itchy, and watery eyes, and swelling around the eyes. The fluid from the nose is usually clear. Symptom onset is often within minutes following allergen exposure, and can affect sleep and the ability to work or study. Some people may develop symptoms only during specific times of the year, often as a result of pollen exposure. Many people with allergic rhinitis also have asthma, allergic conjunctivitis, or atopic dermatitis.

<span class="mw-page-title-main">Rhinitis</span> Irritation and inflammation of the mucous membrane inside the nose

Rhinitis, also known as coryza, is irritation and inflammation of the mucous membrane inside the nose. Common symptoms are a stuffy nose, runny nose, sneezing, and post-nasal drip.

<span class="mw-page-title-main">Food allergy</span> Hypersensitivity reaction to a food

A food allergy is an abnormal immune response to food. The symptoms of the allergic reaction may range from mild to severe. They may include itchiness, swelling of the tongue, vomiting, diarrhea, hives, trouble breathing, or low blood pressure. This typically occurs within minutes to several hours of exposure. When the symptoms are severe, it is known as anaphylaxis. A food intolerance and food poisoning are separate conditions, not due to an immune response.

<span class="mw-page-title-main">Allergen immunotherapy</span> Medical treatment for environmental allergies

Allergen immunotherapy, also known as desensitization or hypo-sensitization, is a medical treatment for environmental allergies, such as insect bites, and asthma. Immunotherapy involves exposing people to larger and larger amounts of allergens in an attempt to change the immune system's response.

<span class="mw-page-title-main">Hypoallergenic dog breed</span> Type of dog

A hypoallergenic dog breed is a dog breed that is purportedly more compatible with allergic people than are other breeds. However, prominent allergen researchers have determined that there is no basis to the claims that certain breeds are hypoallergenic and, while allergen levels vary among individual dogs, the breed is not a significant factor.

In medicine, animal allergy is hypersensitivity to certain substances produced by animals, such as the proteins in animal hair and saliva. It is a common type of allergy.

<span class="mw-page-title-main">Peanut allergy</span> Type of food allergy caused by peanuts

Peanut allergy is a type of food allergy to peanuts. It is different from tree nut allergies, because peanuts are legumes and not true nuts. Physical symptoms of allergic reaction can include itchiness, hives, swelling, eczema, sneezing, asthma attack, abdominal pain, drop in blood pressure, diarrhea, and cardiac arrest. Anaphylaxis may occur. Those with a history of asthma are more likely to be severely affected.

<span class="mw-page-title-main">Milk allergy</span> Type of food allergy caused by milk

Milk allergy is an adverse immune reaction to one or more proteins in cow's milk. Symptoms may take hours to days to manifest, with symptoms including atopic dermatitis, inflammation of the esophagus, enteropathy involving the small intestine and proctocolitis involving the rectum and colon. However, rapid anaphylaxis is possible, a potentially life-threatening condition that requires treatment with epinephrine, among other measures.

<span class="mw-page-title-main">Tree nut allergy</span> Medical condition

A tree nut allergy is a hypersensitivity to dietary substances from tree nuts and edible tree seeds causing an overreaction of the immune system which may lead to severe physical symptoms. Tree nuts include almonds, Brazil nuts, cashews, chestnuts, filberts/hazelnuts, macadamia nuts, pecans, pistachios, shea nuts and walnuts.

<span class="mw-page-title-main">Fel d 1</span> Secretoglobin protein

Fel d 1 is a secretoglobin protein complex that, in cats, is encoded by the CH1 and CH2 genes.

Laboratory animal allergy (LAA) is an occupational disease of laboratory animal technicians and scientists. It manifests as an allergic response to animal urine, specifically the major urinary proteins (Mups) of rodents, and can lead to the development of asthma. A study of 5641 workers in Japan who were exposed to laboratory animals found 23.1% had one or more allergic symptoms; globally the prevalence among at risk workers is estimated between 11 and 30% According to the National Institutes of Health, prevention of animal allergy depends on the control of allergens in the work environment. This involves a combination of measures to eliminate or control allergen exposure, including engineering controls, administrative controls, and personal protective equipment.

<span class="mw-page-title-main">Human interaction with cats</span>

Hundreds of millions of cats are kept as pets around the world.

<span class="mw-page-title-main">Allergies in children</span> Medical condition

Allergies in children, an incidence which has increased over the last fifty years, are overreactions of the immune system often caused by foreign substances or genetics that may present themselves in different ways. There are multiple forms of testing, prevention, management, and treatment available if an allergy is present in a child. In some cases, it is possible for children to outgrow their allergies.

The toxicology of fire ant venom is relatively well studied. The venom plays a central role in the biology of Red imported fire ants, such as in capturing prey, and in defending itself from competitors, assailants, and diseases. Some 14 million people are stung annually in the United States, suffering reactions that vary from mild discomfort, to pustule formation, swelling, and in rare cases, systemic reactions followed by anaphylactic shock. Fire ant venoms are mainly composed (>95%) of a complex mixture of insoluble alkaloids added to a watery solution of toxic proteins. For the Red imported fire ant Solenopsis invicta Buren there are currently 46 described proteins, of which four are well-characterised as potent allergens.

<span class="mw-page-title-main">Allergies in cats</span>

Cats exposed to allergens may develop allergies or allergic reactions. Allergies tend to become evident and intensify over extended periods of time and can take years to develop. Some allergic diseases and allergies in cats include feline atopic dermatitis, flea allergy dermatitis, feline-mosquito hypersensitivity, and food-induced allergy. In the case of feline atopy, hypersensitivity to allergens is due to genetic predisposition. However, various allergies may arise due to environmental factors. Allergens, ingested, inhaled, or airborne, can be seasonal or non-seasonal, similar to allergies in humans. Suspected seasonal allergens include but are not limited to pollen, fleas, and mosquito bites; suspected non-seasonal allergens include but are not limited to plastic materials, food, dust, trees, and grass. After exposure to suspected allergens, symptoms may be immediate or delayed, arising within a few minutes to two hours. Symptoms can include both dermatological and gastrointestinal signs such as itchy skin, hair loss and excessive scratching. In cases of feline atopic dermatitis or atopy in cats, pruritic skin diseases may result; however, signs can also include miliary dermatitis, symmetrical alopecia, and lesions of the eosinophilic granuloma complex.

<span class="mw-page-title-main">Fish allergy</span> Type of food allergy caused by fish

Fish allergy is an immune hypersensitivity to proteins found in fish. Symptoms can be either rapid or gradual in onset. The latter can take hours to days to appear. The former may include anaphylaxis, a potentially life-threatening condition which requires treatment with epinephrine. Other presentations may include atopic dermatitis or inflammation of the esophagus. Fish is one of the eight common food allergens which are responsible for 90% of allergic reactions to foods: cow's milk, eggs, wheat, shellfish, peanuts, tree nuts, fish, and soy beans.

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