Dear Daisy Dog
Onyx, my usually black dog, suddenly developed well-demarcated patches of gray hair that make her look like she’s been playing in fireplace ashes. Her skin is normal, and the veterinarian says she’s healthy. What’s causing some of her hair to turn gray?
Onyx’s condition is called poliosis. No one knows its cause or how to treat it.
Poliosis means loss of hair pigment. It’s similar to vitiligo, a patchy loss of skin pigment you may have observed in some people.
The condition is unrelated to polio, that is, poliomyelitis, a viral infection of the gray matter of the spinal cord. The only thing they have in common is the root word “polios,” which is Greek for “gray.”
When poliosis appears without accompanying signs of disease, it doesn’t need to be treated.
Just tell your friends that while we think of onyx as a black stone, the term once applied to black, gray and even white varieties. The stone that matches your dog is now called “gray onyx.”