TL;DR: A swollen vulva and foul odor in dogs often indicate an infection like vaginitis or a UTI, but can signal life-threatening pyometra in unspayed pets. Seek veterinary care within 24–48 hours, or immediately if your dog is lethargic or vomiting.
What causes a swollen vulva and foul odor in my dog?
A swollen vulva accompanied by a foul odor is typically a sign of inflammation or infection. In female dogs, this can be caused by:
- Vaginitis or a urinary tract infection (UTI).
- Skin fold dermatitis around the pelvic area.
- Pyometra, a serious and potentially life-threatening uterine infection (especially in unspayed dogs).
- The progression of a natural heat cycle.
Is a swollen vulva with a foul odor a veterinary emergency?
- The urgency level is classified as Medium, requiring a veterinary evaluation within 24 to 48 hours.
- The presence of a foul smell strongly suggests a bacterial infection that requires medical intervention.
- Seek immediate emergency veterinary care if your dog is also showing signs of lethargy, vomiting, or excessive thirst.
How does taking a photo of the area help with triage?
- A clear visual record allows a veterinary professional to see the exact color and consistency of any discharge, such as whether it is bloody, cloudy, or green.
- Photos allow the clinical team to assess the severity of the swelling and prioritize your dog's case.
- Images provide clues as to whether the issue is localized to the skin or originating from within the reproductive tract.
Clinical Context (Merck Veterinary Manual)
In bitches, vulvar swelling and foul odor can be indicative of several conditions. Pyometra, a hormonally mediated diestrual disorder with secondary bacterial infection, is commonly seen in older bitches after estrus. Factors include progestational compounds, estrogen administration, and post-breeding infections, leading to cystic endometrial hyperplasia and bacterial growth. Vaginal hyperplasia, a proliferation of the vaginal mucosa due to estrogenic stimulation during proestrus and estrus, can also cause a mass protruding from the vulva. Other differentials include metritis, vaginitis, and cystitis. Vaginal cytology can help determine the nature of any vulvar discharge.
Chapter: Reproductive, Urology
Source: The Merck Veterinary Manual, 11th Edition (Page 1398)