How are people allergic to most dog breeds but not all?

It's not true that most people are allergic to most dog breeds. Dog allergies are relatively common but are typically specific to certain breeds or families of breeds. The proteins that trigger allergies in people are found in a dog's saliva, urine, and dander (shed skin cells). Some breeds, such as poodles, bichons frises, and Portuguese water dogs, produce less of these allergens than others, making them less likely to trigger allergic reactions. Additionally, people may develop allergies to particular breeds based on their individual sensitivities and exposures.