Anyone who has wrestled with adolescent acne will remember how difficult it can be to eradicate. Cats are often afflicted with a similar condition, called "feline acne" or, more commonly, "chin acne" or "kitty acne". Like acne in humans, its causes can vary, including food allergies, contact allergies, and (some experts believe), stress.
Plastic food dishes have long been suspected as a culprit in chin acne. Plastic is a magnet for bacteria and dirt that work their way into scratches and nicks, reinfecting your cat and/or spreading bacteria to other cats in the household. Veterinarians and other feline experts recommend using only glass or metal food bowls, and daily washing of those, in order to help prevent this common condition.
Stress-related acne can be treated by finding the causes of the stress and eliminating or ameliorating them, if possible. Emotionally cause stress may be relieved by medication, flower essences, or pherome-based products, such as Feliway. Environmentally caused stress might be solved by doing whatever possible to change the environment (move the furniture back that you just moved, or back off and gradually re-introduce that new cat or dog.)
Feline acne starts as small, oily black plugs in the chin, much like blackheads, which may progress to red, itchy bumps, which may become infected. Treatment varies, but most veterinarians will recommend daily cleaning with an antibiotic soap, followed by a topical ointment, either antibiotic, or anti-fungal. Oral antibiotics may also be prescribed, as well as a scrub with hydrogen peroxide.
Severe cases of feline acne may be difficult to eradicate, so you'll want to take your cat to the veterinarian at the first sign of black spots on the chin. Although cats are not embarrassed by acne, as humans are, the condition is still potentially serious, and not to be ignored.