Can Mange Cause Black Spots and Blotches on a Dog’s Skin?

Yes, it can. Long-standing skin inflammation from mange, allergies or infection often causes the skin to darken (hyperpigmentation) and thicken, so black or gray patches can appear where there's hair loss. Demodectic mange, which can cause small dark bumps from blocked hair follicles, is one possible cause.

Darkened skin with hair loss has many other causes as well, including chronic allergies, yeast infections, and hormone problems such as hypothyroidism or Cushing's disease. Some dogs also simply have natural dark spots on their skin that become more visible as their coat thins or as they age.

Because so many conditions look alike, a vet visit is the best way to find out. Your vet can do a skin scraping to check for mites, look for infection, and suggest blood tests if a hormone problem is suspected. Note whether your dog is itchy, since that's a helpful clue. Read more about dog skin rashes and discoloration.

This is general information, not a diagnosis. Please follow your own vet's advice.