What happens when dog saliva gets in your mouth? What to Know

You can be allergic to dog saliva.

While many people believe that pet fur is the culprit of allergic reactions to dogs, many of these allergies actually stem from proteins found in dog saliva.

According to one study, dog saliva contains at least 12 different allergy-causing protein bands. When dogs lick their fur, the saliva dries, and these proteins become airborne.1

The researchers who conducted the study concluded that dog saliva has greater potential as an allergen source than dog dander. The study revealed that a specific protein profile (IgE) differs between dogs, making some dogs saliva more allergic for specific humans who are hypersensitive to this protein.

Dog saliva is antibacterial, but it probably won’t heal wounds.

Dogs often lick their wounds in order to clean them. There may be healing properties in a dog’s saliva, and this may be another reason that they lick their wounds.

Certain proteins in dog saliva called histatins can defend against infection, and research has shown that there are other beneficial chemicals in a dog’s saliva that can help protect cuts from infection.

There is evidence that suggests that wounds licked by dogs heal twice as fast as wounds that were not licked. In one 2018 study, researchers discovered that canine saliva contains various proteins, antimicrobial enzymes, and peptides that make holes in bacterial cell membranes.2

Unfortunately, not all wounds will heal when licked. Moisture and inflammation from licking, and in some cases, the bacteria that lives in the saliva, can slow healing or even make the infection worse.

This is why veterinary visits are recommended for even superficial wounds. Often, your veterinarian will recommend a collar or a bandage to keep your dog from licking their wounds and causing more trauma to the already inflamed area.

Capnocytophaga infections are not nationally reportable, so there is no national estimate of the number of infections that occur every year. Additionally, Capnocytophaga can be easily diagnosed by routine microbiology laboratory tests, so many cases of the disease are likely diagnosed and treated by health care providers without ever being reported to CDC. MicrobeNet, CDC’s online reference library, has received reports of 12 positive cases in the past year. These are likely only the most severe cases or those in which diagnosis was complicated for some reason. However, these do not include the most recent cases that have been reported by the media.

In June, a man in West Bend, Wisconsin, had both hands and lower legs amputated after being infected with the bacterium Capnocytophaga canimorsus, possibly through contact with a dog, according to the Milwaukee Journal Sentinel. Two other recent cases were reported in Wisconsin, according to the paper: a boy aged 3 years who had his fingers and toes amputated after being exposed to C. canimorsus, and a woman who was bitten by her dog and developed rapidly progressing influenza-like symptoms that resulted in her death.

Typically, Capnocytophaga does not cause disease in humans, and most human contact with dogs and cats — even through bites — does not result in illness. However, in rare cases, people can develop illness from this infection. This is most common in people who are asplenic, have a history of excessive alcohol use or have a weakened immune system for other reasons (for example, people who have cancer, HIV, liver disease, or take certain medications like steroids that make it more difficult to fight off infections). In the rare cases when illness disease develops, it can be serious and rapidly fatal without antibiotic treatment. Most people who become ill will begin showing symptoms within 3 to 5 days, but this can range anywhere from 1 day to 2 weeks. Signs and symptoms can include blisters around the bite wound within hours; redness, swelling, draining pus or pain at the bite wound; fever; diarrhea and/or stomach pain; vomiting; headache and/or confusion; and muscle or joint pain. Approximately three out of 10 people infected with Capnocytophaga die, and some infections can lead to death in as little as 24 to 72 hours after symptoms start. If someone does develop clinical signs consistent with Capnocytophaga infection after a dog or cat bite or contact with their saliva, they should seek medical care immediately. Click to enlarge .

Clinical disease is rare, but people can become infected with Capnocytophaga bacteria through bites, scratches or close contact with dogs or cats. Most people who have contact with dogs and cats do not become sick from Capnocytophaga. People with weakened immune systems who already have difficulty fighting off infections are at greater risk of becoming ill.

Many dogs and cats have Capnocytophaga in their mouths (normal oral flora), and it does not cause them illness. Animals can be tested, but a negative result may not mean the animal will always be negative, and the same is true for a positive result. Although animals could be given medicine to kill the bacteria in the short term, they can still get the bacteria again through contact with other animals. It is important that people with weakened immune systems take this into consideration when they are considering getting a new pet. However, it is still important to emphasize that most contact with dogs and cats does not result in a Capnocytophaga infection or any illness. CDC’s Healthy Pets Healthy People [webpage] has tips for these high-risk groups on how to have safer contact with pets: https://www.cdc.gov/healthypets/index.html.

Verify: Can dog saliva cause an infection?

If you’ve seen an influx of furry four-legged friends around your neighborhood (or on your Instagram feed), it’s no coincidence. The COVID-19 pandemic led to a boom of pet adoptions, a trend commonly known as “the pandemic puppy.” Pet rescues and adoption agencies experienced exponential demand in the months following the onset of the pandemic, so much so that the waiting lists to not only adopt but foster became overwhelmingly long.

This new fad for bringing home a new addition to the family makes sense: in a time full of uncertainty and anxiety, pet companionship has shown to be great for our physical and mental health.

As anyone who’s been around a young, overly excited canine companion would know, these friends absolutely adore eating, running (zoomies, anyone?), and covering their beloved humans in big, wet displays of affection. Why do our puppy pals love to lick our faces so much anyway? The answer lies somewhere between evolutionary habits and social conditioning.

When wolf cubs transitioned from their mother’s breast milk to something more solid, they tend to lick the mouths of their adult counterparts for some uh, fresh leftovers. Yum! Knowing this, it’s no wonder our dogs use their super olfactory senses to hop onto our laps for a lick after we’ve devoured a slice of pizza or returned from the gym. As Community Medicine Veterinarian Tierra Price, DVM, MPH points out, “Whether you just finished a steak or if you just came in from a workout, the taste of your face may be the appeal for some dogs.”