You may not have paid particular attention to your dog's nipples until you noticed something out of the norm. As with other physical signs and symptoms, nipple discoloration in dogs can be a biological tap on your shoulder suggesting that something in your dog's body is amiss. Whether you own a male or female dog, don't ignore this symptom hoping it vanishes on its own; nipple discoloration may warrant further investigation by your veterinarian.
Female Hormones at Play
One of the most benign causes of discolored nipples are hormonal changes taking place in nonspayed female dogs. If your intact female was bred, consider that reddening and enlargement of the mammary gland along with increased body weight and abdominal distension are potential signs of pregnancy. Expect these changes to occur in your dog's second trimester, generally by Day 40 of her gestation. However, also keep in mind that false pregnancies often can mimic the symptoms of a true pregnancy.
The Stress of Nursing
If your dog has whelped recently, the pups frequent suckling and gnawing may cause local irritation. Additionally, puppy nails may scratch the nipples causing bacteria to enter the skin and creating an ugly case of mastitis that requires veterinary attention. It's not a bad idea to trim those nails starting at 2 to 3 weeks of age and to keep an eye out for reddened, almost purple breast tissue that is swollen and warm along with other accompanying signs of illness.
A Local Irritation
In some cases, the skin over your dog's nipples may become irritated just as any other parts of the dog's body. This is especially true if just one or a few nipples appear discolored. In dogs who love to rub their body on the carpet or rug, the friction may cause trauma to the nipples, which may become irritated. Excessive licking or scratching due to skin conditions or contact allergies also may trigger a local reaction and discoloration.
The Dreaded "C" Word
Dogs can get breast cancer with mammary tumors appearing as firm, nodular masses. Upon being palpated the masses may feel like granules under the skin. The skin may appear ulcerated or infected and the nipples may appear swollen, red and may emit a local discharge. Don't just assume your dog is immune from this condition just because he's a male; occasionally, mammary tumors develop in male dogs as well. Any suspect nipple discoloration warrants investigation from your vet to rule out a possible malignancy.
- Adelaide Animal Hospitals: Pregnancy And Your Dog - An Overview
- Web MD: Signs Your Dog Is Pregnant
- Lowchen Australia: Canine Mastitis
- Dog Owner's Home Veterinary Handbook ; Debra M. Eldredge, DVM, Liisa D. Carlson, DVM, Delbert G. Carlson, DVM, James M. Giffin, MD
- Canine Reproduction and Whelping: A Dog Breeder's Guide; Myra Savant-Harri
- What's Wrong with My Dog?; Jake Tedaldi
- Canine Cancer: Mammary Cancer
- Vet Street: Breast Cancer in Dogs and Cats
Adrienne Farricelli has been writing for magazines, books and online publications since 2005. She specializes in canine topics, previously working for the American Animal Hospital Association and receiving certification from the Certification Council for Professional Dog Trainers. Her articles have appeared in "USA Today," "The APDT Chronicle of the Dog" and "Every Dog Magazine." She also contributed a chapter in the book " Puppy Socialization - An Insider's Guide to Dog Behavioral Fitness" by Caryl Wolff.