Remember a lot of the people you are visiting have weakened immune systems. Don't feel that you are being unreliable by canceling an appointment. As long as you notify the facility in advance, it is much more responsible to wait until you are well. It is important to be aware of which residents are allergic to dogs. This should be documented in the resident's record.
Some people have reactions to the dander by touching the dog, others by inhaling it in the air.
Many people with asthma are allergic to animal dander. Be sure that you and your dog don't approach a person with a known allergy to animals. If his or her roommate would like a visit, it will be necessary to visit somewhere other than in the room, perhaps in a community room, or in the hallway. Included in your packet are reprints of charts which list some of the possibilities for zoonotic infections and diseases. Be sure to keep your dog's toenails trimmed, and file any rough edges if necessary, as many elderly people have fragile skin which tears easily.