I am a retired allergy nurse for what my thoughts are worth. Here is what I know. People with allergies need to keep their allergies in perspective but be able to lead a fulfilling life. There are so many wonderful non drowsy allergy meds on the market that makes living with allergies so much easier than it used to be. No one can live allergy free, so the best thing to do is is minimize the allergans the best you can. Just because a person has allergies, does not automatically make them allergic to dogs. Some people have food, or seasonal allergies, for example. Does not automatically make them allergic to dogs or cats. Very few cats, perhaps the hairless kind, are good for people with cat allergies. Cat allergies for some reason, cause more symptoms than for other pets that shed.
Non shedding dogs are best for those with dog allergies. Be careful of mixed breeds if the mix includes dogs that shed. Some of the breeds that are best for people who want dogs are: poodles, bichons, maltese, King Charles Cavaliers, and shih tzu. There are more that I can't think of right off hand. These all need periodic haircuts and grooming, depending on how you like their coats. Frequent brushing, and periodic baths, with conditioner will help keep dander down.
I personally have had 2 shih tzus, my last one, Sophie, I had to put to sleep right after Thanksgiving. They are wonderful dogs with sweet dispositions, and are very good with kids. They lived 14 and 13 years respectively without many problems. (My daughter on the other hand, has a wonderful boxer with horrendous allergies! Lots of vet bills, as our vet said she is the most allergic dog he has ever seen! ) Funny!
I hope his helps. Sorry to be so wordy. Mary