Acid reflux in dogs: symptoms, tests and treatment

Overview

Reflux means contents flowing backwards from the stomach into the oesophagus. An individual episode does not establish reflux disease, because reflux also occurs in healthy dogs without obvious harm. Reflux disease means backflow causing troublesome signs or complications. Stomach contents may also reach the throat and affect the airways.

Reflux was identified in 41% of healthy dogs undergoing swallowing imaging. With another method, scintigraphy, reflux appeared in 12/12 healthy dogs, or 100%. These figures describe backflow detected by different methods rather than disease prevalence. Assessment also considers volume, frequency and resulting injury.

Causes

The reflux barrier and oesophageal clearance may weaken

At the stomach–oesophagus junction, the lower sphincter, diaphragm and supporting structures form a barrier to backflow. The diaphragm supports this junction by externally compressing the abdominal part of the oesophagus. Temporary sphincter relaxation or reduced tone can allow stomach contents to move the wrong way. Saliva and oesophageal contractions help clear refluxed material. After swallowing, a contraction wave carries food towards the stomach. Oesophageal stretching can also trigger another clearing wave without a new swallow. The upper sphincter acts as a barrier against oesophageal contents reaching the throat and airways. Slow clearance prolongs lining exposure to harmful contents.

Acid is not the only damaging factor. Bile acids and digestive enzymes can irritate tissue even when contents are not highly acidic. Slow stomach emptying and distension from large meals can increase reflux.

Anaesthesia and hiatal hernia alter the functional balance

Anaesthesia and certain medicines reduce lower oesophageal sphincter tone and predispose dogs to reflux. Repeated vomiting is also associated with reflux and oesophageal irritation. In a sliding hiatal hernia, part of the stomach moves through the diaphragmatic opening towards the chest. Sphincter pressure then decreases, making backflow easier.

Strong inhalation against narrowed upper airways increases negative chest pressure and can worsen herniation and reflux. Digestive and airway signs may therefore share a functional cause.

Risk factors

In flat-faced breeds, hiatal hernia and reflux often occur alongside upper airway narrowing. French Bulldogs are a particularly well-described example. Herniation and associated signs also occur in dogs without short muzzles. Muzzle shape alone therefore does not determine a symptomatic dog's diagnosis.

Previous anaesthesia, ongoing vomiting and oesophageal dysfunction increase the possibility of reflux. A feeding tube crossing the stomach–oesophagus junction can also promote backflow. A small hiatal hernia may cause no signs despite appearing during investigation. Risk is assessed alongside swallowing, breathing, previous procedures and feeding history.

Typical symptoms

A dog's signs cannot directly establish whether they experience the burning sensation humans call heartburn. Signs can involve the oesophagus, swallowing or airways. You may notice:

• Repeated lip smacking or empty swallowing.
• More drooling than usual.
• Regurgitation of food or fluid into the mouth or onto the floor.
• Difficulty swallowing, pain when eating or reduced appetite.
• Neck extension during swallowing.
• Night-time restlessness or repeated changes of position.
• Chronic coughing, a hoarse voice or other airway signs.

Regurgitation usually occurs without the strong abdominal effort typical of vomiting. Vomiting generally involves abdominal contractions and retching. Lip smacking and surface licking can also result from oral problems or other pain. Hiatal hernia-related regurgitation, vomiting or breathing difficulty may worsen with excitement and exercise. Mild oesophagitis may cause few signs.

Complications and consequences

Persistent reflux can cause inflammation and ulcers in the oesophageal lining. Scarring can narrow the oesophagus and impair food passage into the stomach. Contents accumulating above a narrowing increase backflow and aspiration risks. Aspiration means food, secretions or stomach contents entering the airways. Pneumonia can result.

Repeated entry of small amounts into the trachea can also cause non-bacterial lining inflammation. Stomach contents have experimentally impaired clearance maintained by canine tracheal cilia. Repeated microaspiration has also been linked to chronic bronchitis in dogs.

Around 46–65% of benign oesophageal strictures have been associated with reflux during anaesthesia. This does not mean the same proportion of all anaesthetised dogs develop a stricture. Painful swallowing and regurgitation after anaesthesia have begun at a median of 7 days after the procedure. Hiatal hernia has a guarded outlook because some dogs develop complications such as aspiration pneumonia. Prolonged disease can involve malnutrition and repeated aspiration pneumonia.

Diagnosis at the vet

The signs, feeding and breathing are assessed together

Investigation establishes whether the problem is regurgitation, vomiting, difficulty swallowing or coughing. An owner's video helps distinguish these events. Your vet reviews diet, previous anaesthesia and medicines. Swallowing movements may result from periodontal disease, an object between teeth or a tonsillar foreign body, for example. Examination of the mouth, throat and breathing helps identify diseases causing similar signs.

No single test resolves every reflux disease case. Diagnosis combines signs, lining assessment, swallowing function and reflux measurements when needed. Plain X-rays do not reliably identify mild oesophagitis. Normal chest images do not exclude intermittent reflux or small aspiration events visible only during dynamic imaging. Chest X-rays are nevertheless useful for assessing airway complications.

Endoscopy assesses damage and dynamic imaging assesses function

Endoscopy shows the oesophageal lining and any stricture or foreign body. A videofluoroscopic swallow study shows food passage, oesophageal movement and possible hiatal hernia. A hernia can slide back and forth, so it may not appear during every examination.

Oesophageal pH monitoring measures acid exposure and its relationship to observed signs. Acidity measurement alone may miss weakly acidic reflux. Combined impedance and pH testing can distinguish acidic and weakly acidic reflux. Anaesthesia during endoscopy limits assessment of normal oesophageal movement, even when lining damage is clearly visible. Some referral hospitals can also investigate reflux and small-volume airway entry using scintigraphy without anaesthesia. Pressure measurement provides more information about oesophageal muscle function but is not routine at every practice.

Treatment

Feeding and the harmfulness of stomach contents are modified

Treatment depends on severity, lining damage and the underlying cause of reflux. Food is offered as smaller, more frequent meals instead of large portions. Soft, low-fat, low-fibre food may be used for oesophagitis. Weight loss forms part of treatment for an overweight dog.

Acid suppressants reduce stomach acid irritation and support lining healing. However, a proton pump inhibitor does not itself stop stomach contents flowing backwards. Suitable medication may therefore also include a medicine supporting stomach emptying and lower sphincter function. Your vet may consider the lining protectant sucralfate. Your vet chooses and monitors medication; do not start human heartburn products yourself.

Underlying structural or airway problems are treated

Significant airway narrowing in a flat-faced dog may need surgery, which can also reduce reflux. A hiatal hernia causing mild signs is generally first treated with medicines reducing reflux and associated inflammation. Surgery is recommended for severe or longstanding symptomatic hernias. Hernia type and size influence treatment choice. A scarred oesophageal stricture can be treated during endoscopy. Severe oesophagitis may need a tube into the stomach to support nutrition. Pain is treated with appropriate medication.

Pneumonia caused by aspirated contents is assessed and treated separately. A response to combined reflux treatment may take 6–8 weeks to become apparent. This describes waiting for clinical response rather than a medicine course to follow at home. Worsening breathing or swallowing during treatment nevertheless needs immediate reassessment.

Prevention

Avoiding large meals and following the agreed diet can reduce reflux. Correcting excess weight forms part of management. Meal changes alone cannot eliminate reflux associated with hiatal hernia or airway narrowing. Treating the cause of repeated vomiting helps protect the oesophagus.

Before anaesthesia, previous regurgitation and reflux disease are considered when selecting medication and the wider plan. Reducing acidity may lessen injury even if reflux continues. The practice gives individual fasting and medication instructions.

Important for dog owners

Record exactly what happens during signs: does the abdomen contract, does food reach the mouth, or is your dog coughing? Take a short video when safe. Note links to meals, rest and previous anaesthesia. Record all foods, treats and any changes.

Monitor eating, drinking, weight and any breathing changes. Do not force a dog with swallowing difficulty to eat or drink. Always report previous reflux before sedation or anaesthesia. Follow the agreed feeding, medication and follow-up plan. If treatment helps but regurgitation continues, tell your vet. New breathing difficulty or severe swallowing pain needs emergency assessment.

Frequently asked questions

Does lip smacking always mean heartburn?

Lip smacking and repeated swallowing have several possible causes. Mouth or throat problems and other pain may look like heartburn to an owner. Suspected reflux therefore requires assessment of the exact event, its relationship to eating and other findings suggesting disease.

How do reflux, regurgitation and vomiting differ?

Reflux is stomach contents rising into the oesophagus. Regurgitation returns contents to the mouth, generally without abdominal effort. Vomiting is active and usually involves abdominal contractions. Describing or recording the event helps your vet distinguish these and choose appropriate investigations.

Does reflux disease show on plain X-rays?

Plain X-rays provide limited information about oesophageal lining inflammation. Endoscopy shows lining damage, while swallowing video imaging assesses passage and oesophageal function. A sliding hernia may not appear during an individual examination. Tests are therefore chosen according to signs and previous findings.

Can reflux cause coughing without vomiting?

Dogs can have reflux-related airway signs without obvious gastrointestinal signs. Contents reaching beyond the oesophagus can be associated with coughing and aspiration. Investigation of persistent coughing therefore also considers swallowing and links to eating. Breathing difficulty needs prompt assessment regardless of the presumed cause.

Why does acid medication not always stop regurgitation?

Acid medication changes stomach acidity, but a proton pump inhibitor does not itself prevent backflow. Bile acids and enzymes can also cause harm in less acidic contents. Feeding, stomach emptying and a possible hernia are therefore considered in the overall treatment plan.