they are not "non"alergenic, they are hypoallergenic. "Having a decreased tendency to provoke an allergic reaction" meaning they are less likely to cause alergetic reactions in most people, but I have heard of a few cases of people being alergic to them
Some people will tell you that no dog is "non allergenic" and some will tell you that this breed is. My experience is that most people who are allergic to dogs will not have a reaction to a maltese. This is because they have hair rather than fur and less dander. They are typically bathed more often also.