Dehydration in Dogs: Causes and Best Treatment

It is not uncommon for pet dogs to become dehydrated, particularly when they are young or old. While they are very unwell, they tend to eat and drink much less and also lose more fluid due to processes such as running a fever, panting, vomiting, and passing diarrhoea.

Most cases of mild dehydration can be easily treated at home, as long as they are addressed promptly. However, dehydration can have a severe impact on a dog's health, particularly if left untreated for an extended period.

Knowing how to identify dehydration and quickly treat it is an important part of puppy and dog ownership. Identifying when dehydration requires vet care is not always easy, so don’t hesitate to seek veterinary care if you have any doubt.

What is Dehydration in Dogs?

Dehydration is when a dog is not intaking enough water to function normally. It occurs when more water is lost than is being absorbed.

How Does the Canine Body Maintain Fluid Balance?

Dogs employ various methods to maintain a normal fluid balance, which they do ‘behind the scenes’ without conscious effort. The brain and kidneys play the biggest role in this.

The hormones ADH (anti-diuretic hormone) and aldosterone, as well as thirst mechanisms, help control the amount of water drunk and the amount excreted.

Why Hydration is Essential for Organ Function and Recovery

Without adequate hydration, proper circulation to organs and tissues would not occur, and toxic waste would not be removed efficiently by the kidneys.

What Causes Dehydration in Dogs?

There are several ways a dog can become dehydrated. It can happen to any dog, but is seen more commonly in young puppies and seniors.

Insufficient Water Intake or Poor Diet

If a dog doesn’t take in enough fluids through drinking water or their diet, this can lead to dehydration.

This can occur if they are eating very salty or dry foods, or if their water bowl is left empty for an extended period.

Heat, Exercise, and Environmental Stress

Anything that leads to the body trying to cool itself (via sweating or panting) actively can quickly deplete the body’s fluid reserves.

Some of the more common instances of this occur when a dog is too hot, when they engage in strenuous activities, or when they’re highly stressed, such as when experiencing distress and prolonged periods of panic due to a noise phobia during a fireworks display.

Vomiting, Diarrhoea, or Fever

Anything that puts the body under severe stress and leads to fluid being rapidly expelled can quickly cause dehydration. This occurs with gastroenteritis, as well as when there is a fever.

Parvovirus is a good example of a virus that rapidly depletes dogs of fluids, causing severe dehydration.

Underlying Medical Conditions and Medications

A wide range of medical issues can increase a dog's predisposition to dehydration.

Some of the more commonly seen would include diabetes, chronic kidney failure, Addison’s, severe colitis, or urinary tract infections.

Medicines that increase thirst, such as corticosteroids and diuretics, can also have a significant impact. Owners should be aware that these dogs require significantly more water than usual.

What Are the Signs and Symptoms of Dehydration?

The symptoms of dehydration can develop rapidly, occurring within a matter of hours. Many can be detected at home by owners.

Early Signs: Lethargy, Dry Nose, and Sticky Gums

With mild dehydration, you may notice your dog’s gums are a little tacky and that their nose feels dry. They may also sleep more and be less eager to exercise.

Severe Symptoms: Collapse or Sunken Eyes

As dehydration progresses and reaches levels above 10%, more serious signs can occur. These would include visibly sunken eyes, weakness, collapse, a weak pulse, and coma.

How to Perform the Skin Elasticity Test at Home

It is a good skill to be able to check your dog’s skin test. You pinch the loose skin over the scruff of the neck and monitor how slowly or quickly the skin returns to its normal position.

Check the skin tent when your dog is healthy, and notice how it just takes a second or so. When dehydrated, it can take 2 seconds or more to rehydrate. Be aware that this test has limitations in young dogs with loose scruffs and older dogs with less elastic skin.

How Do Vets Diagnose Dehydration in Dogs?

Vets are well versed in diagnosing canine dehydration, and checking a dog’s hydration status is a typical part of any physical exam.

Physical Examination

Your vet should check your dog’s skin tent and also examine their gums to assess moisture levels. Dry or tacky gums indicate dehydration.

When the gums are pressed, the colour should blanch and then return to normal within 2 seconds. This is a crude way of assessing circulation.

Blood Work and Urine Analysis

Several parameters measured on blood and urine tests can indicate hydration levels. We look at things like the urine concentration, as very dark and concentrated urine indicates dehydration.

We also examine creatinine levels, electrolytes, blood urea nitrogen, packed cell volume, and lactate, all of which can be elevated when a patient is not adequately hydrated.

How to Treat Dehydration in Dogs

Once we’ve established that your dog is dehydrated, we want to try to get their hydration levels back to normal as soon as we can.

Safe At-Home Rehydration for Mild Cases

If your dog is only slightly dehydrated and is coping well, you can often improve its condition at home. This includes:

• Offering high-moisture foods such as wet dog food.
• Ensuring water bowls are topped up.
• Adding water to meals.
• Offering rehydration solutions and dog-safe soups and bone broths.
• Offer small sips if your dog is vomiting.

When to Seek Professional Help

Not every case of dehydration can be managed from home. If in doubt, it is always advised to seek veterinary care.

Veterinary Fluid Therapy: IV and Subcutaneous Options

When a dog cannot hold water down or refuses to drink, we often provide fluids from a route other than the oral one.

In general, this will be the intravenous route, which is very effective. Other routes, including subcutaneous and intraosseous routes, can also be used.

Treating the Underlying Cause to Prevent Relapse

In addition to supplementing fluids, we need to address the cause of excess fluid loss, whatever that may be.

This can include providing an anti-nausea injection, anti-diarrheal medicine, or administering antibiotics.

How to Prevent Dehydration in Dogs

There are some simple things you can do from home to help make dehydration less likely.

Daily Hydration Habits and Clean Water Access

Encourage regular water drinking by always having full bowls of fresh water available.

Some dogs prefer mineral water over tap water, and they won’t want to drink if the water is dirty or near something that smells foul (like the bin).

Keeping Dogs Cool During Heatwaves

Pay extra attention during heatwaves, especially if you have a senior, thick-furred or brachycephalic breed.

Always stick to shaded areas and go for walks during the cool parts of the day. Be aware of the signs of heatstroke, so you can act swiftly should any begin.

Special Care for Puppies, Seniors, and Sick Dogs

These dogs are more prone to dehydration and struggle to cope when dehydrated.

They need us to monitor their hydration levels more closely, and they should be seen promptly if they show signs of even mild dehydration.

Routine Vet Care

Preventative healthcare, such as annual vaccines, regular check-ups, and worming prevention, is the cornerstone of good health and goes a long way towards preventing stomach upsets and diarrhoea.

When is Dehydration a Veterinary Emergency?

Contact and emergency vet if your dog is not improving quickly or if you feel they’re not coping.

Red Flags That Require Immediate Treatment

Some of the more concerning signs would include:

• Weakness or lethargy
• Dry or tacky gums
• Sunken eyes
• Persistent vomiting
• Food and drink refusal
• Loss of skin elasticity
• Very dark urine

Why Early Intervention Saves Lives

Dehydration is easily reversible, as long as the patient is seen promptly and the underlying cause is addressed.

Delaying treatment until a dog is severely dehydrated can mean they struggle to recover and that their circulation is negatively affected.

We also want to prevent abnormal salt levels or low blood pressure, both of which can cause dogs to become suddenly unwell.

Discover More About Dehydration in Dogs

Feel welcome to contact us to discuss canine dehydration further, and if you have any concerns about your dog.

Dehydration in Dogs FAQs

How can I tell if my dog is dehydrated?

Some of the telltale signs of dehydration include tacky gums, a prolonged skin tent, and reduced energy levels.

What should I give my dog to rehydrate at home?

Offer your dog tempting, high-moisture foods and add water to meals. You can also provide rehydration solutions or bone broth alongside their water.

How can I prevent my dog from becoming dehydrated?

While it is not always easy to prevent dehydration, it is helpful always to have fresh water available and to see a vet promptly if your dog is losing a lot of fluids.