Dogs are wonderful pets to have around but an allergic reaction to dog dander will prevent people from enjoying the affectionate and loyal companionship of a dog. The sneezing, the debilitating fatigue, the watery eyes and the runny nose are often attributed to the presence of a dog. An allergic reaction believed to be caused by dog hair would prevent a dog lover from taking a dog for a pet. Some breeds are hyped to be hypoallergenic but a person that was weakened by allergies would think twice to get a dog.