By Zoe Forward, DVM, Dipl. ABVP (canine/feline) Notice any black debris on your cat's chin, or maybe even pimple-like lesions? Then your cat has chin acne. This is not a hormonal problem. Actually, we are not entirely certain why some cats get these lesions. Some cats only experience one episode in their life, while others may have cyclic or near-constant disease. There are several suspected causes, including poor grooming habits, abnormal hair follicles with overproduction of sebum, virus infection (calicivirus, herpes virus), stress, chin trauma (due to excessive scent marking by rubbing the chin on vertical objects, or from scratching the chin due to underlying allergy), plastic food dish contact allergy, underlying immunosuppressive disease or bacterial contamination from rubbing the chin in food (especially in old dried canned food). SIGNS: Early clinical signs include crusts and plugged hair follicles forming "blackheads" on the chin and lower l...