Julie Liu, DVM
Most of us have talked about environmental flea treatment so often to clients we could do it in our sleep, but when was the last time you advised a client on environmental treatment for cat allergies? Approximately 10 to 20 percent of adults worldwide are estimated to be sensitized to cat allergens, creating both a public health concern and impacting the human-cat bond.
Cat-allergic people can experience sneezing, itchy eyes and throat, skin rashes, wheezing, coughing, asthma attacks, and even anaphylaxis, leading some households with a severely allergic family member to make the painful decision to rehome or relinquish their cat to a shelter. In a 2021 review of human allergies to cats and cat ownership, allergies were listed as one of the top five reasons for relinquishment in the US-based studies, and were often cited as a reason for avoiding pet ownership.
Before you advise clients to get their own Mr. Bigglesworth, cat allergens are not produced in the hair shafts, and no truly hypoallergenic cat currently exists because all cats produce some allergens. Scientists have classified eight different proteins produced in saliva, skin, serum, and urine that cause cat allergies in people. The biggest culprit by far is Fel d1, which is produced primarily in a cat’s saliva and sebaceous glands and spread through the coat via grooming. Hair and dander are shed in the environment, and the small molecular weight of Fel d1 allows it to stay airborne for days, clinging to surfaces and triggering an IgE response in allergic individuals.
Three areas of focus have been described to help people manage their cat allergies: the human, the environment, and the cat. Antihistamines, nasal sprays, washing hands and clothes after contact, and allergy immunotherapy may provide some relief of symptoms, and veterinarians should encourage cat parents to consult a human allergist. Management of the environment can be helpful but time-consuming and eternal, like Sisyphus continually pushing a giant ball of cat dander up a hill. Environmental recommendations include frequent washing of bedding and surfaces, vacuuming at least weekly using a HEPA filter, replacing carpet with bare floors, and using a low-permeability mattress and pillow covers.
The final area of management, the cat, is often the most challenging, both with implementation and effect on the human-cat bond. In a 2020 online survey of over 2,000 American cat parents, 84 percent of those surveyed reported that they would ignore a doctor’s advice to relinquish their cat to manage allergies, and 20 percent of those surveyed reported they would keep the cat and get a new doctor. Other suggestions, such as avoiding physical contact with the cat and banning them from the bedroom, are difficult if not impossible for cat lovers, resulting in stress and frustration for cat and human alike. Studies that investigated bathing cats to remove allergens have shown mixed results, with some reporting return to baseline Fel d1 levels as little as one to two days after bathing.
In 2020, Purina released Pro Plan LiveClear, a promising over-the-counter diet that takes a new approach to cats and Fel d1. LiveClear is coated with chicken egg-derived, anti-Fel d1 antibodies known as IgY, which neutralize Fel d1 in cat saliva by blocking the portions of Fel d1 that bind to human IgE. Studies have shown a significant reduction of active Fel d1 in the saliva of cats fed the diet, with one study showing a decrease of ≥ 20% of active Fel d1 in 82 percent of the treatment group. Even though LiveClear targets salivary Fel d1, a study of hair samples from cats fed the control diet from 0 to 2 weeks and LiveClear from 2 to 12 weeks showed a mean 47 percent reduction of active Fel d1 by the end of the study.
Similar to many problems in veterinary medicine, a multimodal approach may work best for allergies to cats, and LiveClear provides an appealing option for allergic households without the need for a prescription. By educating clients about options such as diet and environmental treatment, veterinary professionals can play a huge role in strengthening the human-cat bond, and even improve retention of feline family members in their homes.
Resources
- Sparkes AH. Human allergy to cats: A review for veterinarians on prevalence, causes, symptoms and control. Journal of Feline Medicine and Surgery. 2022;24(1):31-42. doi:10.1177/1098612X211036793
- Sparkes AH. Human allergy to cats: A review of the impact on cat ownership and relinquishment. Journal of Feline Medicine and Surgery. 2022;24(1):43-52. doi:10.1177/1098612X211013016
- https://habri.org/cat-allergens-research/ (accessed 4/6/22)
- Satyaraj E, Li Q, Sun P, Sherrill S. Anti-Fel d1 immunoglobulin Y antibody-containing egg ingredient lowers allergen levels in cat saliva. Journal of Feline Medicine and Surgery. 2019;21(10):875-881. doi:10.1177/1098612X19861218
- Satyaraj E, Gardner C, Filipi I, Cramer K, Sherrill S. Reduction of active Fel d1 from cats using an antiFel d1 egg IgY antibody. Immun Inflamm Dis. 2019;7(2):68-73. doi:10.1002/iid3.244
This article was reviewed/edited by board-certified veterinary behaviorist Dr. Kenneth Martin and/or veterinary technician specialist in behavior Debbie Martin, LVT.
