People seem to think that hypoallergenic means "non-allergenic." It doesn't -- it means "slightly allergenic." Wikipedia puts it plainly:
Some breeds are certainly less allergenic than others. It would be wrong to say that poodles or similar breeds are non-allergenic, though.Hypoallergenic pets still produce allergens, but because of their coat type or absence of fur or absence of a gene that produces a certain protein, typically produce fewer allergens than others of the same species. People with severe allergies and asthma may still be affected by a hypoallergenic pet.