Since your pergunta was if any breeds of cachorros were
truly hypo-allergenic, the answer is no (at least as far as science is concerned). It's not an easy pergunta to answer since there's no governing body over the term hypo-allergenic. The term is used as a marketing tool to convince people that there is a reduced tendency for people to have allergic reactions (like for some cosmetics or pillows or, in this case, dogs).
The idea that some breeds of cachorros are hypoallergenic has been mostly a marketing ploy por breeders of certain cachorros (usually those that do not shed as much or have pele, peles with similar properties to human hair) to bolster sales which has been picked up por the media and general public and spread as fact over the last couple decades (creating a brand new industry of designer hypo-allergenic cachorros and bolstering the sales of breeds that had been declining like poodles).
Most people who are allergic to cachorros are allergic to the saliva and dander (skin flakes). Even a totally hairless dog produces dander (and obviously saliva). It's believed that a dog that doesn't shed as much (like a poodle) will have less airborne dander (the theory being that since the dander can cling to the pele, peles and if the pele, peles stays on the body then it won't be in the air) and so produce fewer allergens, but studies have not shown people to be less allergic to poodles than to other breeds.
There is also a much promoted myth concerning cachorros with hair vs. cachorros with fur. This is another marketing ploy - all pele, peles is comprised of hair (of course) and although the aspects and properties of the hair can differ (some a mais similar to human hair), the allergens are not affected.
If you're allergic to dogs, then you should either stay away from them entirely or find a dog that you don't seem to react to. (This
link seems to suggest that it is possible for some individuals to find a particular dog (not of any specific breed, but just a lucky dog) that they do not react to.) Otherwise, bathe your dog frequently (once a week) and keep them outdoors to minimize allergen build up indoors.
Here's a link to mais recent artigo on the subject from
link.