I don’t think service animals have to be hypoallergenic.
https://www.ada.gov/regs2010/service_animal_qa.html
> Q26. When might a service dog's presence fundamentally alter the nature of a service or program provided to the public?
A. In most settings, the presence of a service animal will not result in a fundamental alteration. However, there are some exceptions. For example, at a boarding school, service animals could be restricted from a specific area of a dormitory reserved specifically for students with allergies to dog dander. At a zoo, service animals can be restricted from areas where the animals on display are the natural prey or natural predators of dogs, where the presence of a dog would be disruptive, causing the displayed animals to behave aggressively or become agitated. They cannot be restricted from other areas of the zoo.
Edit: also,
https://www.ada.gov/service_animals_2010.htm
> Allergies and fear of dogs are not valid reasons for denying access or refusing service to people using service animals. When a person who is allergic to dog dander and a person who uses a service animal must spend time in the same room or facility, for example, in a school classroom or at a homeless shelter, they both should be accommodated by assigning them, if possible, to different locations within the room or different rooms in the facility.