Why is my dog’s back red?

A dog’s red back can have several causes. One is skin allergy from an allergen like detergent, food or environment. Another is skin infection from bacteria or fungus. Some dogs get skin inflammation from summer heat or high humidity, showing as a red back.

Also, parasite infection like fleas or mites can redden the back. If the redness comes with itching, hair loss or swelling, take the dog to a vet to confirm the cause and treat properly.