It happens often. At every age and in every condition. Acute diarrhoea – much like vomiting – is a symptom frequently observed in our four-legged friends. In the majority of cases, these are clinical signs linked to gastrointestinal disorders of little severity, which can resolve on their own or quickly following appropriate symptomatic treatment. Other forms, such as certain types of viral gastroenteritis and haemorrhagic gastroenteritis, have a more fulminant character and are potentially life-threatening. We asked Dr Giuseppe Febbraio, veterinary surgeon specialising in gastroenterology and animal endoscopy on the MyLav team, to shed some light on this condition.

How is acute diarrhoea diagnosed, and when should we be concerned?
The diagnosis of acute gastrointestinal conditions is largely based on the dog's clinical history and the results of clinical and laboratory tests carried out. A rational symptomatic treatment is often indicated to improve symptoms and accelerate recovery. Patients showing depression, dehydration and fever in association with acute diarrhoea must be carefully assessed and subjected to tests to identify any systemic abnormalities. Furthermore, a thorough consultation involving precise questions put to the owner makes it possible to establish whether the diarrhoea – and any associated vomiting – stems from a gastrointestinal condition, whether it is secondary to organ dysfunction, or whether it is the result of clear errors in the management of a nutritional plan. It therefore becomes important to gather information about the environment in which the dog lives, any ongoing treatments, the diet, and possible exposure to toxins and infectious agents.

Are there differences between acute diarrhoea in young dogs and that in adult or elderly animals?
Young dogs are predisposed to gastroenteric conditions of a dietary, parasitic and infectious nature. In adults, vomiting and diarrhoea should raise suspicion of dietary or metabolic disorders, or alterations in intestinal permeability. Animals that live outdoors or are allowed to roam freely are the most exposed to toxic, parasitic and infectious gastroenteric conditions. Environmental stressors can also trigger episodes of acute and intermittent diarrhoea, but these are more common in working dogs (police dogs, search dogs used in the event of earthquakes or avalanches, for example) or competition dogs.

What role does diet play in the onset of acute diarrhoea in dogs?
Dietary problems (that is, adverse food reactions, ingestion of spoiled food or indigestible materials) are among the most common causes of acute diarrhoea. Dietary errors are more frequent in dogs than in cats, and it therefore becomes essential for the veterinary surgeon to know the type of diet the animal follows. For example, the ingestion of poor-quality food, of bacterial enterotoxins resulting from the administration of contaminated raw meat (particularly in summer), overfeeding (a frequent error with small-breed animals), abrupt or frequent changes of diet, an excess of table scraps perhaps given as a "treat" to the dog, and changes in feeding habits are the most common causes.

Furthermore, when the diet is changed suddenly, some dogs (puppies in particular) are unable to digest or absorb certain nutrients until the intestine has adapted. It is worth emphasising that we are not talking about food intolerance or food allergy (terms that are often overused), but rather referring to the need for intestinal enzymes to adjust to new ingredients. Trials with "hypoallergenic" diets are more appropriate for pets presenting with more chronic clinical signs.

Errors in dietary management are especially common in summer and in early autumn, owing to the concern of many owners about a momentary loss of appetite in their animals – often (though not always) caused by the heat. Indeed, when the weather is warmer, there is a greater tendency to give table scraps or food that does not suit the daily habits of a house dog, which may already be worn down by the heat, by climate change, or – if male – by females on heat during the autumn period. Sound management of the nutritional plan is therefore the best solution for treating and preventing acute diarrhoea.