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Causes of Dog Nipple Discoloration

Dog Nipple Discoloration

If you notice dog nipple discoloration, you may be concerned about it and may be wondering what's the cause. As with any color changes in body parts, nipple discoloration in dogs warrants some investigation and the best way to investigate is by taking the dog to the vet. There are various causes for dog nipple discoloration and some of them can be quite serious, while others may be just temporary, being part of certain stages of a dog's life.

female dog

A Matter of Hormones

In intact (not spayed) female dogs, nipple discoloration can be just a benign sign due to hormonal changes. If your intact female dog was recently in heat and bred, a slight reddening of the nipples along with enlargement may be an early sign of pregnancy.

However, if your female dog was in heat and you are certain that she did not mate with a male dog, consider that nipple discoloration may be indicative of phantom pregnancy, also known as a false pregnancy.

Whether your dog is pregnant or undergoing a false pregnancy, the nipple discoloration should subside once the effects of the hormones are out of the way (after giving birth or after going through the false pregnancy)

And what about nipple discoloration in male dogs? Male dogs are sensitive to the effects of hormones too and therefore changes can also case nipple discoloration, If that's the case, an estrogen/testosterone ratio test can beperformed, explains Critical Care Vet, a veterinarian specializing in emergency veterinary care.

Effect from Nursing

help dog make more milk

If you notice nipple discoloration in a female dog who is nursing, then this could be a result of irritation from the puppies' repeated suckling and scratching at the nipples. Many professional breeders trim the puppies' nails in hopes of reducing the irritation.

Not much though can be done for the irritation derived from the puppy's teeth. Usually, this starts to happen when the puppies' teeth are getting particularly sharp around 3 weeks of age.

Often, this time coincides with weaning (the process where puppies stop depending on mother's milk and start exploring solid foods). You can call it Mother Nature's way to make mother dog reluctant to nurse so the puppies will investigate new food sources rather than milk. Offering puppy gruel and mush at this stage is therefore a good way to encourage the puppies to start the weaning process.

If mother dog's nipples appear discolored during this time, consider keeping an eye for signs of an infection. Any scratches causing broken skin may allow bacteria to seep in causing a case of mastitis, an infection of the dog's nipples which requires veterinary attention. Signs of trouble include nipples that are red, almost purple, swollen and warm to the touch. Mother dog may be reluctant to nurse and the milk may appear discolored.

A Possible Irritation

dog scared

Irritation of the skin can affect any body parts and when it affects breast tissue, it can also cause discoloration of the dog's nipples. How does a dog's breast tissue end up getting irritated? There can be several culprits.

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If your dog likes to rub his belly on the carpet or against a specific rug, there are chances that the localized irritation and nipple discoloration may occur as a result of friction. Another potential cause is excessive licking or scratching aimed at breast tissue because of underlying allergies or skin conditions.

Not to mention, possible contact allergies as seen in dogs who lie down on carpets, rugs, floors, or grass and develop a skin hypersensitivity from the use of chemical products such as carpet cleaners, floor detergents or exposure to grass pollen and other potential allergens.

A Sign of Cancer

 Dog mammary cancer

Dog mammary cancer

Cancer is a word that is often dreaded by many dog owners, but it must be mentioned when it comes to any changes in shape, size or color affecting any body part. In this case, we're talking about mammary cancer, which is particularly a concern with intact, non-spayed females.

In this case, the dog's nipples may appear red, swollen and there may be discharge. If the dog owner feels the breast tissue, he or she may feel firm, nodular masses under the skin.

While intact females are most prone to this condition, don't just assume it's impossible for your spayed female of male dog to contract mammary cancer. Male dogs, even though quite uncommon, can get mammary cancer as well.

Mammary tumors can be benign or cancerous in nature, but generally when removed early, they may turn out to be not a long-term concern.

"Even a spayed female can have this potential abnormality and studies have shown that aspiration or poking with a needle will not differentiate benign mammary growths versus cancerous ones so any new grows that are associated with the mammary chain should be removed and pathology done to determine the level of concern."~Dr. Altman, veterinarian

Other Possible Causes 

There are several other possible causes for discolored nipples in dogs. For instance, if the nipple appears black, it could be simply dirt that has accumulated over time. In some older dogs, the nipple's shape and color may change as the dogs age, explains veterinarian Dr. Steph. 

Several skin disorders may cause darkening of nipples and the surrounding skin and one of them is Acanthosis Nigrans, which causes hyperpigmentation. In this condition, because there is chronic inflammation, special cells known as macrophages release melanin which causes a significant darkening of the skin.

As seen, the causes for discolored nipples in dogs can be many. Because of some serious undelrying issues such as infections or even the risk for cancer, it's therefore important reporting to the vet any suspicious dog nipple discoloration you notice in your dog.

 Photo Credits:

  • Mammary tumor in a dog, Joel Mills - Own work Mammary tumor in a fourteen year old Labrador Retriever. The tumor is about eight centimeters in length. It was confirmed to be a carcinoma on histopathology. CC BY-SA 3.0

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