They definitely can be, so do some checking before you buy a certain breed. It might take some time to discover whether or not you are allergic to a particular breed.
You can be allergic to the shed dog skin, hair, saliva, or even their urine. Some of the reactions include nasal congestion, sneezing, itchy and watery eyes, skin rashes, headaches, fatigue, coughing, shortness of breath, wheezing, and serious asthma attacks.
One way to see if you - or your child - develop a reaction is to visit a breeder. Hug the dogs and rub your nose into their fur. Let them lick your bare skin, especially on your neck and inside your arms where the skin is sensitive.