My cat has a new dark blue/black spot on her butt. Should I worry?
Some discoloration/skin changes can be normal with age, however if the area is rapidly changing color, the spot loses hair, is painful, or you notice signs of cuts or infection (open wounds, oozing debris, pain to the touch, etc) it is best to have your vet take a look to rule out issues such as an infection or injury to the area.
I would keep an eye on the spot to monitor for any changes, and keep Sweetie from licking or chewing at it with the use of an Elizabethan (cone) collar as needed, as well as keep the area clean and dry. If the spot doesn't improve or worsens, a vet visit is best.
Updated on September 23, 2025