All good advice above, I am not familiar with hot spots, mange, or yeast as I haven't experienced that with my two yet. The best thingvtomdo if your not sure what it is , is to ask your vet, and have a skin scraping done to get a accurate diagnosis. I am familiar with allergies though , my female Blossom has allergies to chicken, and so we switched their food to Fromms Beef Fritata when they were 7 months old, and both are doing great on this food. I started putting salmon oil in their food, about the same time, and Blossom immediately showed signs of allergies again, so I stopped it for 2 weeks, and she was fine again. I gave her a Benedryl and the symptoms improved. I now give her cod liver oil instead of salmon oil and she tolerates it fine. You can also try coconut oil for the Omegas.
LEARN A LESSON FROM YOUR DOG, NO MATTER WHAT LIFE BRINGS YOU, KICK SOME GRASS OVER THAT AND MOVE ON.