What Makes A Pet Hypoallergenic
Pet allergy is an allergic reaction to proteins found not only in the
  animals' fur or hair but also in saliva, urine, mucous, and hair roots
  and in the dander sloughed from the animals' skin. Thus, the
  widespread idea that "hypoallergenic pets" are those that have less
  hair or shed less is a myth.
  
  Most often, pet allergy is triggered by exposure to the dead flakes of
  skin (dander) a pet sheds. Any animal with fur can be a source of pet
  allergy, but pet allergies are most commonly associated with cats,
  dogs, rodents and horses.
  
  Some dog breeds have been promoted as hypoallergenic because they do
  not shed their hair, shed very little, or have the same pH as human
  hair. However, no canine is known to be completely non-allergenic.
  
  Some cat breeds, especially females are likely to have low levels of
  Fel d 1, the main allergenic protein.
  
  There is only one known hypoallergenic horse breed. The Bashkir Curly
  horse has a uniquely textured coat that lacks the protein (present in
  all other horse fur) believed to be the source of allergic reactions
  to equines.


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