gkamom, it would depend on just why you are allergic to dairy. If you have an allergy to milk protein, you are absolutely correct and should avoid all dairy. If, on the other hand, a person is allergic to lactose, kefir can still be used. I'm seriously lactose intolerant, yet I use kefir - because the kefir uses lactose to 'do it's thing' - it uses up the lactose! When I'm feeling very sensitive to dairy, I just allow it to do a double ferment.
Brendoni - here is a link that explains that information really well. A complete breakdown of what probiotic strains are in home made kefir. If you buy it, you will have to refer to the label.
www.culturesforhealth.com/learn/milk-kefir/milk-kefir-grains-composition-bacteria-yeast/