Q: I recently got a Havanese puppy, Marcos, who was supposed to be hypoallergenic. However, every time I’m near him, I break out in hives, sneeze, and get itchy eyes. Would modifying his diet make him less allergenic? A: I’m sorry to hear you are allergic to your new pup. Unfortunately, no dog is hypoallergenic, and no dietary modifications, supplements, medications, or vaccines have been shown to change that. All dogs produce at least six allergens, substances that can trigger allergic reactions in susceptible people. These allergens are present in dogs’ skin, hair, saliva, and urine. Breeds once thought to be hypoallergenic are those with continuous hair growth that rarely shed. Because of these characteristics, such dogs require monthly grooming, which temporarily removes some of their allergens. However, these supposedly hypoallergenic breeds still produce as much allergen as nonhypoallergenic dogs. In a 2011 study, researchers measured canine allergen levels in …