Acne is a disease of adult cats. It begins as an accumulation of comedones ("blackheads") on the chin. Careful viewing through the hair will allow you to see them; they may look like dirt. It will be more difficult to see them on a cat with a dark hair coat on its chin. The disease may remain at this stage for many months unless it becomes infected with bacteria (most commonly) or fungi. If that happens the chin becomes swollen and very angry in appearance. The cat becomes sensitive and resists touching and treatment.
Acne is most often diagnosed based on its characteristic appearance, sometimes called a "dirty chin." When infection occurs, it is even more characteristic of acne as the chin is not the site of other common infections.
Treatment begins with clipping of the chin. This permits cleaning and application of medication. Because the cat's chin may be rather sensitive, sedation may be required to accomplish adequate clipping and initial cleaning.
Treatment is continued at home. The pores of the skin are opened with the application of heat. A wash cloth is placed under hot water and the excess water squeezed out. This hot pack is placed on the chin for 2-4 minutes. When it is removed, topical medication is applied. There are several effective medications available, and their choice is partially determined by the presence of absence of infection.
If infection is present, antibiotics or antifungal drugs may be given orally.
This disease will recur in many cats. At the first sign of return, begin hot packing the chin and applying the topical medication. If this does not control the problem, you cat needs to be re-examined by your veterinarian.