Q. Hi our dog ronnie is scratching a lot and we have discovered a really bad red raw sore quite big under his chin on his neck he is 10
DAVID ELBEZE, DVM, MRCVS
A. Itching is a common symptom for dogs at any age and breed. The most common cause of scratching is fleas so even if you don't see any, treat anyway (with a good quality flea treatment ex advantage).
Other common reasons for scratching are allergies- this could be to food, grass, treats, plants and many other things. This is usually difficult to confirm as the cause often remains a mystery, but it can still be treated with various meds.
Other possible reasons are mites, skin infection and tumors.
If the flea treatment doesn't help, it would be best to take him to the vet.