My Dog's Nipple is Leaking - Dog Nipple Discharge

If you are worrying about discharge from your dog's nipple, one of the first things to consider is their sex. Both female and male dogs have nipples, but only the females are strictly functional. This is because they use them to nurse their young after birth and before they are weaned onto solid food. Male dogs have nipples which are essentially vestigial. All mammal embryos begin as female, it is only later on that maleness develops^[1]. Male dog nipples are a leftover element of this experience.

With female dogs, there are different considerations to make if you see discharge from their nipple. The most important factor is pregnancy. Some people may think that a dog will only lactate after they have given birth. However, pregnant female dogs can start the lactation process a few days or even a week before they give birth to their litter. In these cases, the discharge will be of a clear or milky consistency.

The cause of milk production, is a neuropeptide known as oxytocin stimulates milk production during breastfeeding and uterine contractions during labor^[2]. If the dog starts releasing oxytocin earlier, then milk production may also begin earlier. We should know not to touch or squeeze the lactating dog's nipples. This is because doing so could interrupt the process or even cause infection which can be passed on to the weaning puppies.

While we might think of discharge due to lactation as only being white in color, it is also normal to see a slightly yellow discharge occurring before birth. With any type of nipple leaking in female dogs, it is only problematic when the dog is not pregnant, nor have they recently given birth.

In cases where the female dog is not pregnant, but they are showing signs as if they were, we may be encountering a false pregnancy. Clinical pseudopregnancy in dogs is a syndrome observed in dogs that are not pregnant. They will show clinical signs as if they were pregnant such as nesting behavior, enlarged breasts and lactation^[3].

If we see that our female dog looks as if she is lactating or there is a white or yellowish discharge from their nipples, we need to know if she is pregnant. If she has been sterilized and has had no contact with a male dog, then it is likely this is not the case. If so, it is possible that the dog is experiencing a pseudopregnancy. In these cases, the leakage could be due to higher quantities of the hormone prolactin which is related to milk production.

Canine pseudopregnancy occurs between 6 and 12 weeks after a dog's estrous cycle where these hormone levels rise. Physical and behavioral symptoms of a dog with pseudopregnancy include:

• Nesting (finding a comfortable spot as if she were to raise pups)
• Digging
• Weight gain or anorexia
• Mammary gland enlargement
• Aggression
• Over-protectiveness
• Excessive licking
• Lactation
• Mothering of objects

The last symptom on this list usually involves a toy. The dog will mother it as if they were her own offspring and take it somewhere to look after them. Their aggression might come when you try to take this object away as the dog can defend it as if it were their own. Some female dogs might go into a state of depression during a pseudopregnancy.

Physically, the dog's abdomen may enlarge and, in rarer cases, vomiting and diarrhea might occur. Again, we should not manipulate the breasts as it can lead to infection and other problems. Mastitis (something we'll look into further below) can occur which results in inflammation and can be painful. The symptoms of pseudopregnancy in dogs usually leave on their own accord. However, it can come back after another estrus cycle ends. In these cases, it is highly recommend the dog is sterilized.

While a phantom pregnancy may be the cause of a dog's nipple leaking fluid, this does not happen in male dogs. There are also other types of fluid which can leak from the nipple. We look at some of these reasons below for both male and female dogs.

As we stated above, it is possible for some yellowish discharge to occur prior to lactation in female dogs. However, there are other types of yellow discharge which might be more concerning, especially if it becomes green. If it occurs shortly after the mother has given birth, it could be a case of acute septic mastitis. This is because the puppies can agitate the nipples during suckling and allows bacteria to enter the nipple.

Affected female dogs will have a fever, become depressed and may refuse food. Infected and swollen breasts in dogs are usually those closest to the groin area. They may become painful and take on a bluish color. The yellow or green discharge is due to the infection. Hygiene is also an important factor as dogs in unclean environments may have an increased risk of developing bacterial infection. The dog's milk may contain a little blood or take on a green color. However, it is possible for the breasts to be enlarged, but the milk is still white.

Dogs which have just given birth might also develop mastitis due to galactostasis. This is the when the mammary glands are overloaded with milk during the parturition period, i.e. after they have birthed their puppies^[4]. Due to the enlargement, the milk is unable to be released and the result is mastitis. Other causes of mastitis in dogs include mammary gland tumors and mammary gland hyperplasia (the latter being a kind of benign tumor).

Treatment of mastitis will depend on the cause. In case of infection, antibiotics will normally be prescribed. However, if the cause is galactostasis then the first course of treatment should be to prohibit feeding. In terms of tumors, whether malignant or benign, surgery will most likely be undertaken. If the mastitis is left untreated, the result could be gangrene or even death.

Another of the worrying types of discharge is when the dog's nipple is leaking clear fluid. Since a male dog does not produce milk, it is very unlikely you will see white fluid from their nipple. Clear fluid is often in the form of serous fluid which is part of the inflammatory stage of immune response. With this in mind, the following causes of clear fluid discharge in dogs occurs in male and female dogs:

• Mastitis: although the mastitis may not be septic, some swelling may result in a clear fluid discharge from the nipple. Once the infection progresses and sepsis develops, you are more likely to see green discharge.
  
  
• Hormonal imbalance: various health problems in a dog can lead to hormonal imbalances. Although it is associated with females, hyperestrogenism can occur in male dogs and result in nipple discharge. Another reasons males may have a hormonal imbalance is due to prostate problems such as prostate cancer in dogs.
  
  
• Traumatic injury: although discharge may be on the breast, it doesn't mean it is coming from the breast. If the dog receives an injury to the breast tissue, the trauma can cause a wound which leaks clear fluid, leading to green discharge if it becomes infected.
  
  
• Infections: other types of infection can cause a male or female dog's nipple to leak clear fluid. The color and consistency of this discharge will depend on the type of infection, but clear fluid occurs in the early stages of wounds. This is because it is serous fluid which gathers during the inflammatory stage.
  
  
• Cysts or tumors: cysts and tumors can be the result of injury, infection or various diseases. They can be benign or malignant, depending on the underlying cause.

If your dog is leaking blood from their nipples, it won't always look red like fresh blood. Instead, the color of the dog's nipple discharge might be coffee brown or similar. As we stated above, it is possible that mastitis will be accompanied by blood leakage. However, there are other causes which need to be considered.

If your dog has a dark brown or reddish liquid leaking from their nipple, but it is not fresh, it may be due to the presence of a tumor. This can occur in one or several of the dog's breasts. Both cancerous and non-cancerous tumors can cause lumps to occur. It will require an examination and tests by a vet to determine if a lump is cancerous.

With breast cancer in dogs, the main symptom is a painless mass that sometimes causes ulceration of the skin and bleeding. This type of tumor runs the risk of metastasis to other parts of the body, especially the lungs. The treatment requires surgery, although it will depend on how far the disease has progressed. There is a much higher breast cancer risk in unsterilized dogs, only one of the important reasons for sterilization. We should also pay attention to any changes in our dog's breast tissue, especially in dogs over six years of age. If we detect any leakage, inflammation, pain or hard lumps, we need to take our dog to the veterinarian.

Blood leaking from a dog's nipple might have a less life threatening reason. Abscesses can occur when the dog has an injury or a foreign body has entered the skin. These may have a mixture of blood and/or yellowish or green discharge. The abscess grows as pus becomes trapped underneath. The abscess may leave on its own accord, but it does rub the risk of further infection or becoming septic. For this reason, it is important to go to the vet for treatment.

This article is purely informative. AnimalWised does not have the authority to prescribe any veterinary treatment or create a diagnosis. We invite you to take your pet to the veterinarian if they are suffering from any condition or pain.

If you want to read similar articles to My Dog's Nipple is Leaking - Dog Nipple Discharge, we recommend you visit our Other health problems category.