Why am I allergic to certain cats and dogs but not others?

Some have me in hives on my face, others I seem to be immune to. Why?

It may be their dander. Some have it and some don't. Some just have less of it.

Again the reason many people are allergic is because of the dandruff that dogs and cats have, some have less some have more. And based on the severity of your allergy you may not be allergic to cats and dogs that have little dander. My mother for example isn't allergic to many dogs. where as My brother is severely allergic to all cats/dogs despite differing amounts of dander.

they all have different hair and soalso dander.some have alot and some don't.just depends all on the animal and also the living condition, if it lives outside in the dirt you could have allergies to that as well.

ALL cats and dogs have dander - it's just what breeds you react to more, OR perhaps certain ones you've encountered have been bathed more, brushed more, or you were exposed to them in a house that's cleaned more and had less of a reaction.Also, there is NO such thing as a true "hypoallergenic" dog; there are dogs that typically cause fewer allergic reactions in people and those dogs are preferred for people with allergies.

do the cat you arn't alergic to not clean themselves very much? This will sound weird but most people are actaully alergic to the saliva/urine though dander is still a cause- know werid! also sometimes that cats fur traps mold/pollen so there all kind of odd thingshttp://www.acaai.org/public/advice/pets.htm

Cats with longer hair shed more so you might be allergic to them and immune to shorter hair cats(or hairless!) Dogs like poodles, lagotto romagnolos, portugese water dogs and other curly haired dogs dont shed or shed very little.