TL;DR: Constant lip licking in dogs is typically a sign of nausea or oral discomfort; it is usually not an emergency unless accompanied by signs like bloating or retching. Providing your vet with a video or photo of the behavior can lead to a faster and more accurate diagnosis.
Why is my dog constantly licking their lips or smacking their mouth?
When a dog constantly licks their lips or smacks their mouth, it is often a physical response to discomfort. While it can occasionally be a behavioral sign of anxiety or stress, it is most frequently triggered by excessive salivation. This extra saliva is often a byproduct of nausea, oral pain, or gastrointestinal upset. It is your dog's way of trying to manage the fluid buildup or soothe an irritating sensation in their mouth or throat.
When should I worry about my dog constantly licking their lips?
- Low Urgency: If your dog is acting normal, eating, and has a steady gait, monitor the behavior for 24 hours and schedule a routine exam.
- Emergency Action: Contact an emergency vet immediately if the lip licking is accompanied by unproductive retching, a bloated abdomen, or extreme lethargy.
How can a photo or video help my vet diagnose the lip licking?
- Capturing Behavior: A video allows your veterinarian to see the frequency and intensity of the licking, which often stops once the dog arrives at a stressful clinic.
- Oral Identification: A clear photo of the inside of the mouth (if safe to take) can help identify broken teeth, inflamed gums, or foreign objects stuck in the roof of the mouth.
- Efficient Diagnosis: These visual aids ensure a more accurate and efficient diagnosis during your triage or appointment.
Clinical Context (Merck Veterinary Manual)
Constant lip licking in dogs can be attributed to various causes, including cheilitis, lip wounds, foreign bodies, irritants, and extension of infection from the mouth or other body areas. Cheilitis can result from direct extension of severe periodontal disease or stomatitis, bacterial dermatitis, parasitic infections, autoimmune skin diseases, and neoplasia. Clinical signs of cheilitis include pawing, scratching, or rubbing at the mouth or lip, halitosis, excessive salivation, and anorexia. Chronic infections may present with discolored, moist, and matted hair around the lip margins, accompanied by a thick, malodorous discharge overlying hyperemic and sometimes ulcerated skin. Stomatitis can also cause lip licking due to contact ulcers ("kissing ulcers") where the lip or cheek mucosa contacts the tooth surface. Diagnosis of canine stomatitis is based on clinical observation of typical oral lesions after excluding other causes, with biopsy and immune profiling also recommended.
Chapter: Dermatology
Source: The Merck Veterinary Manual, 11th Edition (Page 364)