my 13-year-old shepard mix has been itching her belly a lot recently and there is a lot of discoloration. it’s looks irritated. she also has a couple of missing patches of fur on her back and tail. there are red scabs on her skin where her fur is missing. i gave her a bath 3 days ago and applied some ointment i bought at petsmart, but it doesn’t seem to be helping. what do you guys think is the cause of this? my guess is is that it’s either mange or allergies. any product recommendations on what could help would be appreciated. thanks!