Do you mean hypo-allergenic? It's important to keep in mind that there are NO HYPOALLERGENIC dogs [besides plushies ;-)] I recently read an article that explained that you might have fewer problems with dogs that grow longer hair. A dog that has short hair can grow their hair, shed, grow hair, shed etc. faster than something like a yorkie. However, what you are allergic to is probably the dander, not the hair.
Yorkies do not shed, and have hair instead of fur. The can be good for allergy sufferers depending on what you are allergic to. The require alot of regular groom and brushing, and can be hard to house break. You need to visit them and see if you have a reaction before purchasing one.