Nutmeg had one last year, during a stressful time. Stress evidently heightens the risk. I just washed it and put Neosporin on it. I also added some Omega 3 oil to her diet, which probably didn't really help but it made me feel like I was doing something. That's been her only hot spot so far, knock on wood.
I think some people just keep it clean and don't put on anything. It may depend on the cause? Does your dog with the hot spot have any allergies?