Possible causes of nipple discolouration in dogs

Possible causes of nipple discolouration in dogs: 1. Local irritation. External factors may irritate your dog’s nipples, just like any other part of your dog’s body. This often results in discolouration of one or several nipples. 2. Changes in body hormones. The most common cause of nipple discolouration is hormonal changes in unspayed bitches.