Wash it daily with Keto-C shampoo. Active ingredients are Ketoconazole 1% (anti-fungal) and Chlorhexidine 2% (anti-microbial). My pup has allergies and whenever she starts licking her feet I start washing her feet daily. You leave the shampoo on for about 10 minutes then rinse well and dry. You'll be amazed by how much it helps. It is supposed to be available via prescription, but you can buy it on Amazon without one. Addressing the itching with Apoquel or Hydroxyzine would also help but those are Rx. Hydroxyzine is stronger than Benadryl.
Another thing I have used on hotspots is Potassium Promanganate. It is a granular substance and you only need to use a few grains (literally) to mix with water to make a very light pink solution. Soak the sores in this for 5-10 minutes. It will disinfect and dry up the sores. I used both KMnO4 and Keto-C on my dog this summer, along with Apoquel and antibiotics, for bad hot spot on her tail. It dried up and healed within a week.