Swollen Vulva and Vaginal Discharge in Dogs

Causes of a Swollen Vulva

Heat

Swelling and a bloody discharge are the first signs of heat. The swelling slowly goes down once the heat ends and the discharge stops.^12,13 See dog in heat.

Vaginal overgrowth or prolapse

During heat, some young females develop swollen vaginal tissue that bulges out of the vulva as a pink or red, tongue- or doughnut-shaped mass. Keep it clean, protect it from injury, stop her licking with a cone, and see your vet. It usually shrinks after the heat but tends to come back each heat, and spaying prevents it.^6,7 It's most often seen in a dog's first or second heat, and Boxers, Bullmastiffs and Neapolitan Mastiffs are among the breeds most often affected.¹⁴

Vaginitis

Inflammation of the vagina causes a sticky or pus-like discharge, licking, frequent urination and attention from males. In puppies, it's often mild and clears with time.^3,10

Recessed vulva and skin-fold infection

In some dogs, especially overweight and larger spayed females, skin folds partly cover the vulva. Trapped moisture can cause skin infection, licking, a bad smell and repeated urinary infections. Weight loss and cleaning help, and surgery to remove the extra skin works well for severe cases. In one study of 34 dogs, the surgery stopped repeated urinary infections in 84% of the dogs that had them.^11,4,15

Other causes

Urinary infections, allergies and irritants, injuries, and tumors, including transmissible venereal tumors spread during mating, can also cause swelling or discharge. A venereal tumor can cause a bloody discharge that attracts males and is easily mistaken for heat.^2,16,17 In spayed dogs, heat-like swelling can mean a piece of ovary was left behind.^7,2

What Vaginal Discharge Means

• Bloody, then pink or watery: normal during heat^1,2
• Clear to cloudy and sticky in a puppy: often puppy vaginitis³
• Clear to white just before birth, and dark green to black in the first days after it: normal around whelping, but a green discharge before the first puppy needs a vet now^18,2,19
• Pus-like, yellow, green or bad-smelling: not normal. See a vet.^5,2

Dark or Black Skin on the Vulva

Skin that is repeatedly licked, rubbed or inflamed often darkens over time, and this is common in dogs with allergies, skin folds or past infections.⁹ Flat darkening that isn't itchy, painful or changing is usually harmless, but have any color change checked.^2,9 A raised, well-defined dark spot, or one that grows, bleeds or ulcerates, should be sampled, because it could be a skin tumor.^9,20 See lumps and skin tumors on dogs.

What You Can Do at Home

• Clean the area gently with plain warm water and pat it dry. Avoid strong soaps and household cleaners.^5,2
• Don't apply human creams or ointments unless your vet recommends them.
• Use a cone if she's licking or the tissue is sticking out.⁶
• Help an overweight dog lose weight, which can shrink skin folds.^4,11

See also pyometra, urinary infections in dogs and reproductive health in dogs.

Frequently Asked Questions

Why is my female dog's private area swollen?

Heat is the most common reason. If she isn't in heat, or she's spayed, see your vet.

Why is my female dog's private area sticking out?

It's often swollen vaginal tissue during heat. Keep it clean and covered from licking, and see your vet.

What can I put on my dog's irritated vulva?

Plain warm water to clean it. Ask your vet before using any cream or wipe.

Why does my dog keep licking her private area?

Heat, vaginitis, urinary infections and skin-fold infections are common causes.

Why is my dog's vulva turning black?

Repeated licking or inflammation often darkens the skin. Have any change or raised spot checked by your vet.