Dog-breathing is the second-leading cause of death in Ireland after pneumonia, but it’s one of the least understood medical conditions in the country.

Dr Robert C. O’Mahoney, of the National Council for the Prevention of Cruelty to Animals, is one of Ireland’s leading experts on dog-induced allergic reactions.

He says there are many theories about why dogs are allergic, including a “breath-taking” or “breathy” reaction, which may be caused by the saliva of a dog that is choking, and some dogs’ bodies can develop an allergic reaction to their own saliva.

Cats and dogs, which are similar in size, also have the same immune systems.

O`Mahoney believes this is because both animals have been bred to produce an allergy to one another.

Dr O’Malley says the risk of developing an allergic response to other dogs is low and there is a “very high” risk of being diagnosed as a child allergic to a pet, rather than a pet allergic to you.

Dr Coyle says he believes it is the saliva-based allergies to the animals’ own saliva that are most common, with around a third of all dog-related allergies diagnosed as children.

“If the dog has a bad reaction, the parent can often say ‘I’m sorry, we’ve never really understood that dog’s reaction’,” he says.

“But there are some kids that develop a reaction that is very similar to the parent’s reaction, and the parents say ‘Oh, I don’t understand, I’ve never had a bad allergy to a dog’.”

Dr Coyne also says there’s a difference between allergies to saliva and the dog’s saliva, and that in most cases the dog will react to a cat or dog other than its own.

“A cat or a dog is going to react to that,” he says, “because it has a mouth that is completely different to the mouth of the dog.”

The dog has been bred for this, it has been adapted to the environment.

“So the mouth is different to how the dog would normally react, so they’re going to be different to each other.”

Dr Colan says the main risk factor for developing an allergy is not that you’re allergic to any one animal, but rather that you may have an allergic condition which affects both.

“It’s an area that needs more study, but I think the risk is fairly small,” he adds.