Functional Thoughts
The Hypoallergenic Dog
Mar
Written By Amanda Venturino, MS, MSc
Edited By Jessica Hekman, DVM, PhD; Cornelia Kraus, Dr. rer. Nat; Nickala Squire, CTC, FFCP
You may have heard the phrase ‘There is no such thing as a hypoallergenic dog’. This phrase and other similar iterations are often used inaccurately by veterinarians, vet technicians, trainers, and even breeders when communicating about certain dog breeds. The widespread misuse of the term hypoallergenic has created discord in the dog community as misinformation continues to spread. So, what does the term hypoallergenic really mean, and how should it be used? This post will define ‘hypoallergenic’, discuss what it means in relation to dogs, and what additional research is necessary to better understand allergic reactions to various dog breeds.
Definitions
The term hypoallergenic is composed of the root words ‘hypo,’ which means less, and ‘allergenic,’ which means the ability to induce an allergic reaction (1). Therefore, a product or organism that is hypoallergenic is less likely to induce an allergic reaction. An allergic reaction is characterized by inflammation and the presence of IgE antibodies. As a result, symptoms manifest such as asthma, difficulty breathing, a stuffy nose, itchy eyes, and more. Allergens are microscopic immunogenic particles, meaning they are capable of inducing an immune response. In animals these particles can be found in fur, dander, or even saliva (2).
The term hypoallergenic has been used to characterize everything from food to shampoo, cosmetics, and dog and cat breeds. However, the term has no medical basis, as there are no medically defined parameters or set standards for its use. Therefore, it is a layman’s term used to suggest that the majority of people will not be allergic to a particular product (due to a lack of irritating ingredients) or animal (due to traits or genetics). The phrase ‘no dog is 100% hypoallergenic’ is illogical, because hypoallergenic is a comparison term; a hypoallergenic dog is less likely to induce an immune response when compared to other dog breeds. A more accurate statement would be ‘No dog is 100% nonallergenic’. Something that is nonallergenic cannot induce an immune response in anyone. A nonallergenic dog would indeed be a very rare thing, if one exists at all. On the other hand, hypoallergenic dogs – which are less likely to produce symptoms in many people – do exist.
It may be helpful to understand hyperallergenic as a term used to describe something that is more likely to induce an immune response (‘hyper’ – more). One publication noted that 100 million people are allergic to birch pollen, and up to 90% of those people experienced an immunogenic response to the hyperallergenic form of birch pollen, Bet v 1 (3). In this case, a hyperallergenic protein was defined as one that induces an IgE immune response in 90% of allergen sufferers. Currently, no similar definition exists for hypoallergenic, leaving it open to interpretation and controversy within the dog community.
In Relation to Dogs
Jennifer Bishop-Jenkins, a certified master groomer with forty years of grooming experience, has previously described the difference between dogs with hair or fur (11, 12). Though hair and fur are the same on the cellular level, practically speaking, hair and fur are used to differentiate dog coat types. Breeds referred to as hypoallergenic tend to have hair as opposed to fur. As a result, they have reduced shedding. Some examples are poodles, Bichon Frisés, and several terrier breeds (4). This list of breeds is largely based on anecdotal evidence presented by people who are allergic to dogs but report fewer symptoms when in contact with hypoallergenic dog breeds (8). This doesn’t mean that no one will ever be allergic to these breeds, but it does mean that many people who suffer from dog allergies may have fewer or no allergy symptoms in response to exposure to these breeds.
Often people use the amount of shedding a dog produces as an indication of hypoallergenicity. However, current research is lacking between the association of shedding fur and dogs labeled as hypoallergenic. It is thought that dogs who shed may produce a greater quantity of allergens since they will produce more fur and dander in addition to salivary antigens. There are 7 known dog allergens currently described, and of these, the Can f 1 protein is the major allergen (5,6). One study reported no differences observed between the level of Can f 1 protein between hypoallergenic and non-hypoallergenic dogs (7). This may suggest that differences in the amount of allergen produced may not be the answer as to why these dogs are less likely to induce an allergic response in many people.
However, the study did not take environmental factors between households into account. For example, cleaning frequency of the homes and grooming of the dog were not reported. It is likely that high-shedding dogs would require more house cleaning than low-shedding dogs, thus altering the amount of allergen present; moreover, bathing a dog will reduce the amount of shedding and dander produced (10). The authors also failed to describe the method of collection and the number of human members in each household. Furthermore, the study occurred one month following the birth of a new baby, a potentially stressful time for a family with many guests visiting. Increased human activity in a confined space and visitors tracking in dander from the environment could also impact the amount of allergen measured (13). It is likely the setting of this study was not ideal for measuring the concentration of allergens between coat types.
Currently, the most comprehensive study comparing allergens in hypoallergenic and non-hypoallergenic dog households was performed by Vredegoor et al., 2012. Owners were tasked with collecting fur clippings and vacuum collections with special filters within their homes (8). The study reported significant differences in Can f 1 concentrations between breeds as well as between individual dogs of the same breed. The lowest levels of the Can f 1 allergen were reported in Labrador retrievers (8, 9). Poodles, a hypoallergenic dog breed, had the highest level of Can f 1 proteins (8). Carpets held more allergens than solid surface floors, and dogs that swam more had lower concentrations of the protein. While this study reported no differences observed in dogs that were groomed, a previous study found grooming reduced the Can f 1 protein by 84% in hair clippings and 86% in dander samples over an 8-day period (10).
It is difficult to use the results found in current studies to define parameters around what makes a particular breed hypoallergenic. It is also unclear why dog breeds with a hair coat would contain a greater concentration of the Can f 1 protein compared to fur-bearing dog breeds known for heavy shedding. More research is necessary that utilizes consistent collection techniques and compares more dog breeds. The presence of one allergen type by dog breed cannot be the sole technique for evaluating hypoallergenic dog breeds, especially since the term hypoallergenic relates to people exhibiting a lessened immune response to an organism and not necessarily the concentration of immunogenic proteins in the organism. Therefore, studies are needed in which allergy tests are performed on people with known dog allergies to dander samples collected from hypoallergenic and non-hypoallergenic breeds. The differences in the concentration of the immunogenic protein observed in individuals of the same breed also begs the question of whether or not one can selectively breed for dogs that produce less allergens. To the author’s knowledge, no one is yet using the concentration of Can f 1 protein to selectively breed a line of allergy-friendly dogs. This would make for a very interesting research project.
The term hypoallergenic, as it relates to dogs, should be better defined through scientific research and clinical studies. In the meantime, the term will continue to be utilized to describe dog breeds that are suspected or known to be less likely to induce an allergic response. The overwhelming anecdotal evidence of surveys and medical reports clearly demonstrates that some people are less allergic to breeds with hair. A better understanding of how canine immunogenic proteins relate to allergy symptoms will allow for better matching of owners to dog breeds and, potentially, a scientific definition of the term “hypoallergenic.”
Citations
- “Hypoallergenic.” Merriam-Webster Dictionary, 3 Mar 2023. https://www.merriam-webster.com/dictionary/hypoallergenic. Accessed 11 Mar. 2023.
- “Pet Allergens.” National Institute of Environmental Health Sciences. 29 Aug. 2022. https://www.niehs.nih.gov/health/topics/agents/allergens/pets/index.cfm.
- Ahammer, Linda et al. “NMR resonance assignments of a hypoallergenic isoform of the major birch pollen allergen Bet v 1.” Biomolecular NMR assignments vol. 11,2 (2017): 231-234. doi:10.1007/s12104-017-9754-7
- “Hypoallergenic Dogs.” American Kennel Club. Accessed 11 Mar 2023. https://www.akc.org/dog-breeds/hypoallergenic-dogs/page/3/
- Nakatsuji, Masatoshi et al. “Structure-based prediction of the IgE epitopes of the major dog allergen Can f 1.” The FEBS journal vol. 289,6 (2022): 1668-1679. doi:10.1111/febs.16252
- Smallwood, J., Ownby, D. Exposure to Dog Allergens and Subsequent Allergic Sensitization: An Updated Review. Curr Allergy Asthma Rep 12, 424–428 (2012). https://doi.org/10.1007/s11882-012-0277-0
- Nicholas, Charlotte E et al. “Dog allergen levels in homes with hypoallergenic compared with nonhypoallergenic dogs.” American journal of rhinology & allergy vol. 25,4 (2011): 252-6. doi:10.2500/ajra.2011.25.3606
- Doris W. Vredegoor, Ton Willemse, Martin D. Chapman, Dick J.J. Heederik, Esmeralda J.M. Krop, Can f 1 levels in hair and homes of different dog breeds: Lack of evidence to describe any dog breed as hypoallergenic. Journal of Allergy and Clinical Immunology, Volume 130, 4, (2012). 904-909.e7. https://doi.org/10.1016/j.jaci.2012.05.013
- Breitenbuecher, Christina et al. “Protein expression and genetic variability of canine Can f 1 in golden and Labrador retriever service dogs.” Canine genetics and epidemiology vol. 3 3. 22 Apr. 2016, doi:10.1186/s40575-016-0031-3
- Tessa Hodson, Adnan Custovic, Angela Simpson, Martin Chapman, Ashley Woodcock, Rosalind Green. Washing the dog reduces dog allergen levels, but the dog needs to be washed twice a week. Journal of Allergy and Clinical Immunology, vol 103, 4 (1999). ISSN 0091-6749. https://doi.org/10.1016/S0091-6749(99)70227-7
- Bishop-Jenkins, Jennifer. “Fur vs Hair”. June 4 2021. Accessed Mar 16 2023. https://www.groomertogroomer.com/fur-vs-hair/
- Coile, Caroline. “Does My Dog Have Hair or Fur?”. Nov 28 2022. Accessed Mar 16 2023. https://www.akc.org/expert-advice/health/dogs-hair-fur-grooming/
- Niesler A, Ścigała G, Łudzeń-Izbińska B. Cat (Fel d 1) and dog (Can f 1) allergen levels in cars, dwellings and schools. Aerobiologia (Bologna). 2016;32(3):571-580. Doi: 10.1007/s10453-016-9433-7. Epub 2016 Mar 11. PMID: 27616812; PMCID: PMC4996870.