HYPOALLERGENIC HORSES: FACT OR MYTH?
A German study challenges the theory that American Bashkir Curly Horses are less likely than other breeds to trigger allergic reactions in people.
People unfortunate enough to have an allergy to horses experience many of the same symptoms as seasonal allergy sufferers. “The clinical presentation is variable but most people react to horse allergens with the typical symptoms of hay fever, including sneezing, a runny, itchy or stuffy nose and itchy, burning and watery eyes,” says Eva Zahradnik, MSc, of the Institute of the RuhrUniversity Bochum. “In more severe cases, horse allergy can manifest as asthma, including wheezing, coughing, chest tightness and shortness of breath. Reactions of the skin (hives) are also possible but less common than respiratory symptoms.”
Curly Horses have long been reputed to be less allergenic than other types of horses. “This hypothesis is mostly based on experiences of persons allergic to horses,” says Zahradnik. “Several websites, newspaper articles and TV segments report stories of horseallergic individuals who can handle Curly Horses without suffering any allergic reactions.” Preliminary research seemed to confirm these observations, but the reason for the lowallergenic potential of Curly Horses was unclear, which led Zahradnik to devise a new study to test the premise.
Zahradnik’s team collected 224 hair samples from 32 different equine breeds. They also used personal nasal filters to collect dust inhaled by people grooming both Quarter Horses and Curly Horses. They then analyzed all the samples using a new immunoassay that detects the major equine allergen, Equ c 1, and a commercial immunoassay for the minor allergen, Equ c 4.
“Equ c 1, which is found in horse dander, saliva and urine, belongs to the lipocalin family of proteins and is primarily considered to be a carrier of odorants and pheromones,” explains Zahradnik. “Equ c 4 is a major component of horse sweat and it acts like a detergent, causing foam formation on the coat of sweating horses, especially where rubbing occurs. Both proteins are identified as allergens, which are substances that bind to the antibodies [immunoglobulin E (IgE)] responsible for allergic reactions in susceptible individuals.”
The researchers found that---contrary to popular belief---the dander and hair from Curly Horses contained as many allergens as those from horses of other breeds. In fact, the Curly Horses used in this study had higher levels of allergens than horses of other breeds. “The so-called hypoallergenic Curly Horses that we tested in our study had significantly higher allergen levels in hair than the majority of other investigated breeds,” says Zahradnik. “Based on our original assumption, these results were paradoxical, but not entirely unexpected. Similar results have been previously published for dog breeds. Significantly higher concentrations of dog allergen Can f 1 were found in hair of ‘hypoallergenic’ dogs, like the Labradoodle or Poodle, than of ‘nonhypoallergenic’ dogs like the Labrador Retriever. The concept of a hypoallergenic animal is still not supported by scientific evidence.”
Instead of differences between breeds, the researchers discovered a wide variation in allergen concentrations among individuals of the same breed. “These findings indicate that some