Dear Christopher Cat: We’ve recently noticed a change in our elderly cat’s coat. Cleo used to have sleek, shiny hair, but now it’s unkempt, matted and even a bit oily.

She’s not as active as she was when she was younger, but other than that, everything seems normal. What’s causing her coat to change?

Christopher Responds: It sounds like Cleo isn’t grooming herself as much as she used to. The most common reasons are medical problems and pain.

A medical problem can cause her to slow down and not feel energetic enough to groom. Ask your veterinarian to examine her and do some lab work to see if this is the cause.

As we age, many of us cats develop chronic kidney disease, hyperthyroidism and other conditions that are easily treated.

If Cleo’s physical exam and lab work are normal, she may be suffering from age-related aches and pains that make it difficult for her to twist around and engage in the usual acrobatic maneuvers we cats use to groom ourselves.

Research shows that almost all elderly cats have osteoarthritis, also called degenerative joint disease (DJD). Since feline DJD attacks the spine and the joints on both sides of the body, affected cats don’t limp, so it’s hard to diagnose without x-rays.

If your veterinarian concludes Cleo has DJD, ask about supplements or a pain reliever to help her feel more comfortable. When she starts grooming again, you’ll know the medication is working.