What is a common cause of halitosis in dogs and cats, and how should it be evaluated?

• A. Periodontal disease; evaluate with clinical oral exam, charting, dental radiographs to assess subgingival pockets and bone loss; rule out systemic causes if necessary
• B. Kidney disease; evaluation via urinalysis
• C. Diabetes; evaluation via blood glucose
• D. Lung disease; evaluation via chest radiographs

Answer: (A)

Halitosis in dogs and cats is most commonly due to periodontal disease, because the mouth becomes a home for anaerobic bacteria that produce foul-smelling sulfur compounds as plaque and tartar accumulate under the gums. As gingivitis can progress to periodontitis, pockets form and bone loss occurs, creating more niches for bacteria and intensifying breath odor. This makes the oral cavity the primary place to investigate when a pet has a bad smell.

To evaluate properly, perform a thorough oral examination under appropriate anesthesia, since many problems hide beneath the gum line. Chart all findings—gingival inflammation, attachment loss, tooth mobility, plaque and calculus—so you can track disease severity. Obtain dental radiographs to assess subgingival pockets, root morphology, resorption, and bone loss that aren’t visible on a surface exam. Radiographs help stage the disease and guide treatment, such as cleaning below the gum line, periodontal therapy, and extractions when needed.

If halitosis persists or there are signs suggesting another issue, then consider systemic causes and screen accordingly (for example urinalysis to assess kidney function, blood glucose if diabetes is suspected, or other tests based on clinical signs). However, the most likely and commonly treatable source is dental disease, making a focused dental evaluation the essential next step.