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Dog Dehydration: Symptoms, Causes, and Cures

Written by Tamsin De La Harpe


two lab puppies panting

In the warmer weather, dehydration in dogs is one of the most common reasons for vet visits but it’s something all dog owners need to be aware of regardless of the time of year. Just like you, your dog needs water to survive and whilst dehydration can be deadly in extreme cases, it’s really important you’re constantly aware of how much water your canine companion is drinking to keep them healthy and comfortable. 

So whether you are caring for a puppy that is vomiting, or a pug outside on a hot day, keeping your dog hydrated is key to not only keeping them healthy, but alive. So how do you know if your dog is dehydrated, and what can you do to help them?

Puppy Dehydration: Causes

Because puppies are so much smaller than adult dogs, they are more susceptible to dehydration. Excessive water loss can occur if your puppy becomes overheated while playing outside, since puppies are prone to getting so caught up in play, they may not stop to rest and drink water. In addition, your puppy is more at risk of dehydration in hot weather. 

This is especially true for puppies with thick coats, or short-nosed puppies like pugs and bullmastiffs. Having a shorter nose (brachycephalic dogs) interferes with a dog's ability to regulate heat and cool off. This puts them at greater risk of heat stroke and dehydration. 

Keeping fresh water available at all times helps ensure your puppy gets enough fluids to replace the ones they lose throughout the day.

If there is a medical problem like a congenital defect that causes excessive peeing (polyuria), your puppy risks dehydration.

Other causes of dehydration in puppies are medical conditions that cause the loss of fluids, or stop the puppy from ingesting fluids. These include:

  • Vomiting 
  • Diarrhea
  • Lack of appetite
  • Aversion to drinking
  • Fever
  • Excessive panting and drooling
  • Overheating or heat exhaustion

If your puppy is sick and experiences any of these symptoms, they are more likely to become dehydrated because all of these can cause your puppy to lose water. Therefore, it’s essential you’re keeping an eye on your puppy if they’re suffering from a medical condition.

If you are seeing diarrhea in your puppy, you can read our article on dog poop problems here/learn/dog-health/dog-poop-everything-you-need-to-know

Long-haired or double coated puppies with wet coats are also at a higher risk because their coast can prevent wind or air from reaching their skin to cool them down. This means pups with thick or long coats that spend a hot day running on the beach can have water-logged fur that actually makes it harder to cool down, risking heat stroke and dehydration. It’s best to keep checking in with your puppy to ensure they rest in the shade, cool down, and drink plenty of water.

What are the signs of dehydration in puppies?

It’s easy to check if your puppy is dehydrated. Dry mucous membranes, such as sticky gums and a dry tongue, are dogs' first signs of dehydration and their saliva can become gummy or stringy.

Skin elasticity loss is another sign to be aware of. Gently pinch the skin around your puppy's neck and shoulders, or on the top of their forehead. If the skin is hydrated, it will quickly jump back to its original position when you let it go.

However, if your puppy is dehydrated, the skin may "tent," which is when the skin stays pinched and only slowly returns to normal after release.

Another reliable hydration indicator is the capillary refill time (CRT). pressing your finger against your puppy’s gums shows you how quickly the  mucous membranes' blood supply returns to normal. 

By pressing the gum with your finger, you stop the blood flow making the area white. When you take your finger away, the spot should turn pink again quickly as the blood returns.

When your puppy or dog is hydrated, the white pigment returns to its normal pink color in less than two seconds. 

If the CRT is delayed, it is a sure sign of severe dehydration, and if delayed for more than 4 or 5 seconds, it can even cause death.

How do you treat a dehydrated puppy?

Dehydration in puppies is a life-threatening condition that requires immediate medical attention. Among dogs who have died from salmonella or other serious gastrointestinal diseases, dehydration is the most common cause of death. Fluid is drained from a dog's cells when they’re dehydrated. 

Cell death occurs as a result, and the dog's organs eventually begin to shut down. In addition, your dog's body will use up fluid in the blood, thickening it and reducing the dog's blood volume when blood pressure is low. Therefore, in order to rehydrate and restore the puppy's electrolyte balance, he will need fluid therapy. 

Dogs that show signs of dehydration should be given electrolyte-enriched water. You can also give some ice cubes to chew on if the water won't stay in his system. Contact your veterinarian immediately if they refuse to drink at all, or if symptoms like vomiting and diarrhea are severe.

If your puppy is vomiting yellow, you can read about possible causes here./learn/dog-health/dog-vomiting-yellow-12-possible-causes 

Dehydration can only be reversed if the underlying cause is addressed. To avoid further fluid loss, it may be necessary to take a prescribed medication to manage the causes such as diarrhea and vomiting. A puppy may also need to be put on a drip to replace fluids and electrolytes. 

Additionally, your vet may show you how to give subcutaneous fluid to your puppy at home, depending on the needs of your pup. As long as the dog isn't vomiting, it's fine to give them some water to drink. In addition to replacing electrolytes that have been lost, your veterinarian may prescribe products or recommend remedies you might have around the home.

Causes of dehydration in adult dogs

Heat is perhaps the most common cause of dehydration in dogs. Although it should be noted that dogs living on dry food with a low moisture content, may not be ingesting enough fluids and could suffer from mild dehydration for years. This can take its toll on their liver and kidneys over time.

Dogs can’t sweat the way humans do–they can only sweat through their paws– and most breeds struggle to withstand long periods of high temperatures.  A dog's panting and nasal passageway allows them to exchange their warm internal body air for cooler outside air during hot weather. This is their primary means of cooling down and it isn’t as effective as sweating.

Heatstroke can occur if your dog's core temperature rises above 106 degrees Fahrenheit. Your dog's brain, heart, liver, and nervous system can be severely harmed by overheating. For example, seizures are caused by brain swelling, and ulcers are caused by reduced blood flow to the gastrointestinal tract. 

In addition, dehydration damages the kidneys permanently. All of this devastation occurs in the span of a few short minutes. As stated above, brachycephalic breeds like bulldogs, pugs, and the pekingese are particularly vulnerable since their facial structure doesn’t allow them to cool down the way it does for dogs with longer muzzles.

Dogs left in hot cars are obviously at high risk of heat stroke, but they are not the only ones. Other potential factors in heatstroke and dehydration include:

  • Matted fur or water-logged coats on long hair and double coated breeds that traps heat in the body
  • Strenuous exercise in hot, humid weather
  • Heart or lung disease interfering with efficient breathing
  • Confinement without shade and water in hot weather (remember even kennels can become hot boxes in the wrong environment)
  • If your dog has a history of heatstroke

Kidney disease, diabetes, and other diseases that cause excessive urination, vomiting, incontinence/learn/dog-health/dog-poop-everything-you-need-to-know, and the absence of thirst in dogs can also cause dehydration. Dehydration also sets in as a result of the animals' decreased desire or urge to drink water, which is sometimes due to stress or anxiety, not just disease.

It was also found that the most prevalent type of fatal hypovolemic shock in dogs is dehydration. As a result of severe blood or other fluid loss, hypovolemic shock occurs, which is a life-threatening condition. In addition, many organs may stop working as a result of this kind of shock.

Several factors can cause your dog to become dehydrated. While some of the causes may be minor and easily avoidable, others may be the result of more serious underlying conditions that must be addressed. In the event that you are still unsure about the cause of your pet's dehydration after considering all of the possibilities, it is best to consult a veterinarian to obtain a more accurate diagnosis.

What are the signs of dehydration in adult dogs?

A dry mouth and sticky gums are two of several dog dehydration symptoms. More subtle signs of dehydration include: 

  • Sunken eyes 
  • Muscle spasms
  • Dry nose
  • Lethargy or apathy
  • Vomiting
  • Diarrhea 
  • Refusal to eat
  • Thick drool or saliva
  • Shaking and trembling
  • They also show signs of shock, such as collapsing

Similar to puppies, dehydration can be seen in an adult's skin elasticity and you can use the gums to check your dog’s CRT.

What do I give my dog for dehydration?

Every day, dogs require approximately one ounce of water per pound of body weight. Therefore, if they lose fluids due to vomiting or diarrhea, they should drink more water to make up for the loss. The body loses vital fluids and electrolytes that are crucial to the proper functioning of the various organs.

Giving a dehydrated dog water every few minutes can help them keep it down. Mixing electrolyte replacement powder into the water or giving them ice cubes to lick can also be helpful but always check with your vet before giving them anything that wasn’t specifically prescribed for them. Remember, dehydration can be made worse by letting your dog drink too much water too quickly, which could cause them to vomit and lose more fluids. 

Providing your dog with plenty of fresh water at all times will keep them well-hydrated and avoid dehydration-related issues. Prevent your dog from drinking excessive amounts of water all at once after exercise or eating as this can cause bloat, which is when the stomach twists which is also deadly and usually requires instant surgery to fix. 

If dehydration is treated quickly, the prognosis is good. However, severely dehydrated dogs must be taken to the vet right away. They will likely request that the dog be brought in so they can be rehydrated with intravenous fluids (IV).

Final Word

Dog owners must deal with the serious problem of dehydration proactively. Dehydration occurs when the body's fluid levels fall below a certain level. It’s most common in sick dogs with vomiting and diarrhea, as well as when a dog refuses to eat or drink. Hot and humid environments are also a risk factor.

Severe dehydration can result in serious complications, including kidney and heart failure, and a serious underlying problem could also be indicated by this sign. If you suspect that your dog is dehydrated, you should take him to the veterinarian as soon as possible. If he is dehydrated, your veterinarian will administer intravenous fluids to him while investigating the cause of the problem.