Differential Diagnosis: Ptyalism & Pseudoptyalism

Julie Allen, BVMS, MS, MRCVS, DACVIM (SAIM), DACVP (Clinical), Durham, North Carolina

ArticleLast Updated April 20202 min readPeer Reviewed
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A close-up of a brown Irish Setter with drool hanging from its mouth, set against a blurred natural background. The dog's expression appears calm and relaxed, highlighting its long, wavy fur and distinctive facial features.

Following are differential diagnoses for patients presented with ptyalism/pseudoptyalism.*

  • GI condition

    • Abdominal pain (eg, from visceral stretching)

    • Disease associated with nausea

    • Esophageal disease (eg, reflux esophagitis, megaesophagus, foreign body, neoplasia, stricture, spirocercosis)

    • Gastric dilatation volvulus

    • Gastric ulceration

    • Hepatic failure (eg, hepatic encephalopathy), particularly in cats

    • Hiatal hernia

    • Renal failure

  • Idiopathic or nonresponsive condition

  • Neurologic condition

    • Facial nerve paralysis

    • Idiopathic trigeminal neuritis

    • Infectious disease (eg, rabies,† pseudorabies, tetanus, botulism)

    • Lesions of cranial nerves IX, X, or XII

    • Myasthenia gravis

    • Nausea from vestibular disease

    • Seizures

  • Oral cavity or maxillofacial cause

    • Craniomandibular osteopathy

    • Faucitis

    • Foreign body

    • Immune-mediated disease (eg, masticatory muscle myositis, pemphigus)

    • Lip fold abnormalities

    • Mandibular fracture

    • Oropharyngeal neoplasia (eg, tonsillar squamous cell carcinoma)

    • Oropharyngeal trauma (eg, laceration)

    • Periodontal disease

    • Stomatitis (eg, calicivirus, herpesvirus, FeLV/FIV, caustic agent, electrical burn, ulceration secondary to systemic disease [eg, uremia])

    • Temporomandibular joint luxation or fracture

    • Tongue lesion (eg, linear foreign body), glossitis (eg, uremia, caustic agent, electrical burn), or tumor

  • Physiologic reaction

    • Excitement

    • Hyperthermia

    • Purring

    • Response to feeding

  • Reaction to medication

    • Anesthesia

    • Avermectins (eg, ivermectin, moxidectin/imidacloprid, selamectin) given topically or PO

    • Bitter drugs

    • Cholinergic drugs (eg, bethanechol), anticholinesterase drugs (eg, pyridostigmine), cholinesterase inhibitors (eg, organophosphates)

    • Pancreatic enzyme supplements

    • Pyrethrins/pyrethroids

  • Salivary gland condition

    • Foreign body

    • Salivary gland neoplasia

    • Salivary mucocele

    • Sialadenitis or necrotizing sialometaplasia (ie, inflammation of the salivary glands)

    • Sialadenosis (idiopathic, noninflammatory salivary gland enlargement)

      • May be a form of limbic epilepsy 

    • Sialolithiasis

  • Sepsis

  • Toxicosis

    • 5-hydroxytryptophan (ie, Griffonia seed extract)

    • Bite from a venomous animal (eg, black widow spider, scorpion, toad [Bufo spp], coral snake, sea hare [Aplysia spp])

    • Household cleaner 

    • Human sleep aid (eg, zolpidem)

    • Human tricyclic antidepressant (eg, clozapine)

    • Illicit drug (eg, cocaine, amphetamine)

    • Insecticide/pesticide (eg, boric acid, aldicarb)

    • Metaldehyde

    • Mushroom (eg, Amanita muscaria)

    • Plant/tree (eg, Kentucky coffee tree, poinsettia)

    • Rodenticide (eg, zinc phosphide)

*Differentiating between ptyalism and pseudoptyalism can be challenging; some conditions (eg, oropharyngeal and CNS diseases) can result in both increased salivary production and the inability to swallow.

†Rabies should always be considered in patients presented with drooling.