Dog Losing Fur on Chest

That does sound like itching from allergies or some other skin condition and maybe a longer course of oral steroids would help. But something else to consider, especially if your dog is also tired, is a thyroid condition. When I was a kid, our dachshund started losing hair and gaining weight. The vet kept treating it as a skin condition and wanted to shave off all Snoopy's hair and treat him with special lotions for several weeks. My mom took him to another vet who diagnosed low thyroid hormone. He took a pill every day and was back to normal in no time. He lived to be 15 years old.