Dehydration in Dogs: Signs, Causes, and Treatment

Dehydration in dogs may occur as a result of a variety of situations or diseases and can become dangerous if not addressed. Integrative veterinarian Dr. Julie Buzby discusses the causes of dehydration in dogs and the signs that indicate your dog is dehydrated. Plus, she explains how to treat and prevent dehydration.

Stanleys, Yetis, and Hydro Flasks, Oh my! Water bottles and cups are everywhere you look and may go everywhere you go. Hydration is all the rage, and that’s a good thing overall.

But what about our dogs? They don’t take water along on every errand or walk (although they do manage to find the most disgusting puddles to try to drink out of). Do you have to worry about your dog’s hydration? How do you know if your dog is getting dehydrated?

What is dehydration in dogs?

Dehydration occurs when dogs lose more water from their bodies than they take in. You can think of hydration like a math problem. To maintain adequate hydration, water intake must be greater than or equal to normal losses of water from urination, panting, defecation, and breathing plus any additional losses of water from vomiting, diarrhea, wounds, etc.

In other words, if the dog doesn’t take in enough water to make up for the normal and additional water losses, he or she will become dehydrated. If not corrected, dehydration can have serious, or even life-threatening, effects on the body.

Why is hydration so important?

Hydration is the state of having enough water to perform essential processes in the body, such as organ function, blood circulation, digestion, waste removal, and temperature regulation.

When dogs are dehydrated, many health problems can occur. Blood becomes thicker due to lower fluid content. This forces the heart to work harder in order to pump the blood throughout the body. Plus, it is more difficult for the liver and kidneys to filter toxins out of the body when there isn’t enough water present.

Dehydration also affects the levels of electrolytes such as sodium, chloride, and potassium in the body. Among other things, electrolytes help regulate fluid balance, assist with muscle and nerve function, and move nutrients into cells. Thus, changes in electrolyte concentration due to dehydration can cause problems with the muscles, brain, and other organ systems.

When dehydration is significant enough, the body shuts down, and the dog could die.

What are the signs of dehydration in dogs?

Symptoms of dehydration in dogs can vary depending on how dehydrated the dog is. Dogs who are mildly dehydrated may appear totally normal or only show subtle changes. However, as the level of dehydration increases, the signs become more obvious and more severe.

Veterinarians often estimate dehydration as a percentage of the total body water that has been lost. Using that scheme, 5% dehydration is the point at which dehydration becomes clinically detectable. And dogs with 12-15% dehydration are at risk for shock and death.

However, the exact dehydration percentage isn’t something you really need to worry about as a dog parent. Instead, it is essential for you to know how to recognize the signs of dehydration in dogs and what to do if you see them.

What are the signs of mild dehydration in dogs?

For some mildly dehydrated dogs, you might not see any obvious symptoms. Others may show signs such as:

Skin is slow to return to normal when tented up

Normally, if you gently pick the skin up over your dog’s shoulder blades (not up on the neck) and then release it, it should return to its original position almost immediately. In a dehydrated dog, the skin stays tented. The longer the tent remains, the more dehydrated a dog may be.

• Mild dehydration—skin tent remains for 1-2 seconds.
• Moderate dehydration—skin stays tented for at least 5 seconds
• Severe dehydration—skin does not go back to its normal location.

However, it is important to remember that the skin tent test is less accurate in obese or very thin dogs, older dogs, and those with loose skin or wrinkles.

Tacky gums

When you gently touch a well-hydrated dog’s gums, they should feel moist. However, dehydrated dogs can have gums that feel dry or a bit sticky. Keep in mind that if your dog is also nauseous, he or she may be drooling more. This can make it harder to determine if the gums are tacky because they might just feel slimy.

Safety note: Not all dogs will tolerate their mouth being handled. Please use caution when evaluating your dog’s gums and stop if your dog seems anxious or upset.

Lethargy

Dehydrated dogs are often lethargic dogs. You may notice that your dog seems more tired or sluggish than normal. However, many other conditions can cause lethargy, so it is a non-specific sign.

Consult your vet if your dog is mildly dehydrated

While mild dehydration isn’t an emergency, it can become one if the dehydration worsens. Plus, the condition causing the dehydration could potentially pose a risk to your dog. Thus, it is important to take action. You can sometimes treat mild dehydration in dogs naturally at home (more on this in a bit), but generally it is safest to consult your vet if you are seeing distinct signs of dehydration.

What are the signs of moderate to severe dehydration in dogs?

All of the signs for mild dehydration will be present in a dog who is more significantly dehydrated. Additionally, as the dog continues to lose water, he or she may start showing the following signs of moderate to severe dehydration:

• Thick ropy saliva—Normal saliva is thin, clear, and watery. However, significantly dehydrated dogs may have thick, ropy, and sticky saliva.
• Sunken eyes—As dehydration intensifies, the body pulls fluid from less critical tissues like the fat and skin around the eyes. As a result, eyeballs can appear sunken in the sockets.
• Pale gums—Fluid makes up a large portion of the blood, so in severe dehydration, blood volume drops, too. As a result, the dog may go into shock (a state of insufficient oxygen delivery to the tissues). One of the signs of shock is pale gums in dogs.
• Prolonged CRT—If you press on your dog’s gums with a finger just enough to make them blanch (turn white) and then release the pressure, the gums should go back to a normal color in less than two seconds. This is the capillary refill time (CRT). As dogs become dehydrated, their CRT may become slower (longer than two seconds).
• Weakness—Dehydrated dogs who are in shock may also be wobbly or shaky, collapse, or be unable to stand.
• Cold limbs—To compensate for severe dehydration, the body pulls blood to the core and essential organs. Having less blood in the limbs makes them feel cooler to the touch.
• Increased panting—In some cases, especially if the dog has heat stroke, he or she may be panting more than normal at rest.
• Decreased urine output or darker urine—Dehydrated dogs are attempting to conserve water, so they may have very concentrated (dark) urine and/or low urine production.

Contact your vet immediately if your dog is moderately or severely dehydrated

If you see any of these signs, it is important to make a veterinary visit promptly. Left untreated, dehydration and/or the underlying cause of the dehydration can be fatal.

What causes dehydration in dogs?

Many different factors and illnesses can lead to dehydration. It is important to note that dehydration isn’t a primary ailment itself. In other words, it does not cause things like vomiting or diarrhea. Instead, problems like vomiting and diarrhea result in dehydration.

1. GI disease

Digestive tract problems are the most common causes of dehydration in dogs. This makes sense when you remember that dogs stay hydrated by drinking water. Therefore, any condition that would decrease water intake, increase water loss (such as vomiting or diarrhea), or decrease fluid absorption can lead to dehydration.

Examples of GI conditions that cause dehydration include:

• Intestinal parasites—Roundworms, hookworms, whipworms, giardia, and coccidia can cause water loss through diarrhea. Sometimes, dogs with parasites will also experience vomiting and anemia.
• Infections—Viral, bacterial, or fungal infections of the intestinal tract can cause severe dehydration due to vomiting and diarrhea. Especially among puppies, parvovirus is particularly dangerous, but other infections can lead to dehydration, too.
• Toxin exposure—Ingesting poisonous plants, human medications, and harmful bacteria from raw food can increase the risk of vomiting, diarrhea, or both.
• Intestinal obstructions – When food and water cannot move through the gastrointestinal tract due to an obstruction, persistent vomiting can occur, rapidly leading to dehydration.
• Inflammatory bowel disease (IBD in dogs)—Chronic inflammation of the lining of the intestinal tract increases water loss due to impaired water and nutrient absorption.

If your dog is repetitively vomiting and/or having diarrhea, please make an appointment with your veterinarian promptly. It is important to take steps to find the root cause and stop the vomiting and diarrhea quickly to avoid worsening dehydration.

2. Heat stroke and other heat-related illnesses

Especially when it is hot or humid, there is a risk of your dog overheating when outside or trapped in a warm environment like a parked car. In an attempt to cool down, the dog will pant harder. The evaporation of water from the mouth and tongue helps with cooling, but it is also a big source of water loss. As the dog loses fluid, it becomes harder to circulate hot blood to the extremities and skin to dissipate heat. This makes it even harder for your dog to cool down.

If the dog’s temperature continues to climb to 105° F and beyond, heat stroke in dogs sets in. Then, especially as body temperature approaches 107-109° F, internal organs cannot function properly and begin to shut down. At this point, not only is the dog dehydrated, but he or she is at risk of dying from organ failure and/or clotting disorders.

It is so important to keep your dog cool in summer (and anytime it is warm and/or humid), especially if your dog is more prone to heat stroke. As part of helping your dog stay cool, ensure he or she has free access to clean water, which will also help prevent dehydration.

Safety note: If you suspect your dog has heat stroke, wet him or her with cool (not cold) water, turn on the air conditioner or open the windows in the car, and immediately drive to the nearest veterinary clinic or ER. Heat stroke can be fatal.

3. Reduced water intake

Sometimes the cause of dehydration is as simple as the dog not drinking enough water. Contributing factors include:

• Lack of access to water for a prolonged time
• Neurological issues in dogs, such as trigeminal neuritis in dogs or vestibular disease in dogs, which make it hard for the dog to drink
• Fear of the water bowl or area where the bowl is
• Pain when bending down to drink
• Nausea or GI upset decreasing the desire to drink
• Difficulty breathing while also swallowing due to congestive heart failure in dogs or various respiratory conditions
• Having a fever and not feeling up to drinking enough to make up for additional losses
• Dementia and/or disorientation
• Not drinking enough water after exercise or not being willing to stop and drink in the middle of a strenuous activity

Thus, it is crucial not only to ensure that your dog has access to water at all times but also that he or she is actually willing and able to drink that water.

4. Wounds or burns

Your dog’s skin is an essential barrier against infection, and it is also responsible for holding in moisture. Small cuts or abrasions can heal relatively quickly without impacting the dog’s hydration status. However, larger wounds or burns can lead to excessive fluid loss via increased evaporation and blood loss. As a result, the dog may become dehydrated.

Part of your veterinarian’s plan for managing your dog’s wounds or burns may include ways to help maintain hydration. If not, feel free to ask your vet if dehydration is a concern with your dog’s injury.

5. Systemic diseases such as kidney disease, diabetes, or Cushing’s disease

Under normal circumstances, healthy dogs are very good at conserving water to regulate water balance. However, some medical conditions can increase the loss of water from the body and potentially lead to dehydration.

Cushing’s disease in dogs (excess production of the steroid cortisol) and diabetes in dogs (high blood glucose due to a lack of insulin) both cause increased thirst in dogs and also increased urine volumes. While the dog is drinking more, this may not make up for losses from the urine. As a result, dogs with untreated Cushing’s or diabetes may be dehydrated.

Along the same lines, kidney disease in dogs decreases the ability of the kidneys to concentrate the urine. As a result, the dog loses a lot of water in the urine, especially as kidney failure progresses. Affected dogs could end up becoming dehydrated despite still drinking a lot of water.

6. Medications

Certain medications can also contribute to dehydration in dogs. One of the biggest culprits is diuretics like furosemide (Lasix®). These medications function to pull excess water out of the lung tissue in dogs with failing hearts. But because diuretics work by increasing water loss through the urine, dogs can also potentially become dehydrated while taking them.

7. Old age

Older humans and presumably senior dogs can be more likely to suffer from dehydration. This is thought to occur for a variety of reasons. Older animals and people may feel less of a drive to drink water in general. Plus, senior dogs with canine cognitive dysfunction (dementia) may not remember where the water bowl is or that they are thirsty.

The kidneys of older dogs are also less efficient at conserving water, so they may lose more water through the urine. Finally, pain and poor mobility can potentially keep older dogs from drinking as often or as much as they should.

Interestingly, mild dehydration most likely decreases cognitive function and mood in dogs as it does in people. This may also contribute to some of the cognitive symptoms we see in senior dogs.

8. Seizures

Seizures in dogs occur due to abnormal nerve activity in the brain. They may cause symptoms like altered levels of consciousness, uncontrollable shaking and jerking, or loss of bowel and bladder control. Because of the intense muscle activity and increase in body temperature during the seizure, it is possible for seizures to cause water loss and, therefore, dehydration. This may be why some dogs seem more thirsty than usual or want to go drink water during the post-ictal (after the seizure) phase.

There is a wide range of causes of grand mal seizures in dogs, including epilepsy (the most common cause in young dogs), toxins, liver disease, electrolyte imbalances, and masses or infection in the brain. If your dog has a seizure, give your veterinarian a call and follow his or her advice.

Note: If your dog is having seizures that last more than five minutes or happen back-to-back, make an emergency vet visit immediately. This is known as status epilepticus, and it is an emergency situation.

What is the treatment for dehydration in dogs?

The veterinarian will determine how dehydrated the dog is and what is causing the dehydration. Then he or she will make a treatment plan. Broadly speaking, there are two main goals in treating dehydration:

1. Address the underlying problem to minimize further fluid loss
2. Use fluid therapy (oral, subcutaneous, or intravenous fluids) to replace the fluid the dog has already lost and make up for ongoing fluid losses.

Managing dehydration due to vomiting or diarrhea

For a dog who is dehydrated due to vomiting or diarrhea, the vet will take steps to manage the root issue and the symptoms. This could involve prescribing anti-nausea medications like Cerenia for dogs, anti-diarrhea medications, probiotics for dogs, and/or a bland diet for dogs. Or the vet might need to perform surgery to relieve an intestinal obstruction or administer a dewormer to get rid of parasites.

Depending on how dehydrated the dog is, the vet may simply recommend offering small amounts of water at home. Or he or she might administer subcutaneous fluids for dogs and send the dog home, or hospitalize the dog for intravenous (IV) fluids.

Fluid therapy as part of the treatment for heatstroke

In the case of an emergency situation like heatstroke, the veterinary team will safely cool the dog down. Part of that process may involve giving cool IV fluids. This not only assists in decreasing the dog’s body temperature but also corrects fluid deficits and promotes adequate circulation.

While the dog is recovering in the hospital, the vet will continue to administer fluids as needed to maintain hydration and blood flow to the organs.

Creating a long-term approach to hydration for ongoing problems

Dehydration due to chronic disease, old age, medications, wounds or burns, and other ongoing problems may require a slightly different approach. For example, receiving subcutaneous fluids on a regular basis can be beneficial during the later stages of kidney disease in dogs. And dog parents may use various strategies to encourage drinking in dogs who aren’t taking in enough water to meet their needs.

Work with your vet to find the right approach for your dog

This is far from an exhaustive discussion of managing dehydration because there are many variables at play. Your vet will help you create a hydration plan that is right for your dog’s situation.

Can you treat dehydration in dogs at home?

Ultimately, dogs who are moderately to severely dehydrated, and some dogs who are mildly dehydrated, will need prompt veterinary care. Do not try to treat their dehydration at home.

However, in mild, almost imperceptible dehydration, there are things you can try at home. Plus, the vet may recommend some of these strategies once he or she has evaluated and treated your dog.

1. Provide access to fresh clean water

It is important all the time, but especially in the face of potential dehydration, to ensure your dog has access to fresh, clean water. Sometimes the water dish and the water itself can get grungy from drool, hair, and other material. Washing the water bowl and rinsing it well, then refilling it with cool, fresh water, can encourage dogs to drink.

Some dogs may also like ice cubes in their water or may want to lick ice cubes. (Be careful if your dog likes to chew on ice, as it could potentially fracture or damage a tooth.) Other dogs prefer water from a fountain. Using an elevated bowl can improve comfort when drinking for dogs with neck or back pain. The material of the bowl matters, too. Some dogs prefer to drink out of a plastic bowl, while others like metal or ceramic better.

2. Offer a small amount of low-sodium chicken broth or bone broth

You can try mixing low-sodium chicken broth or bone broth in with food, adding it to water (also provide a bowl of plain water), or giving it to your dog in small amounts. However, it should not replace water for rehydration.

3. Give your dog some canned food

The water content of canned food is much higher than that of dry food. Thus, feeding canned food can be a sneaky way to get more fluid into your dog. However, to really make a difference in hydration status, you need to feed your dog mostly canned food, not just add a scoop of canned food on top of the dry food.

4. Use an oral electrolyte solution designed for dogs

There are also commercially available oral electrolyte solutions for dogs that might be useful in some situations. In a study evaluating the use of an oral electrolyte solution in dehydrated dogs with hemorrhagic diarrhea, the oral electrolyte solution was found to be a safe and effective option for dogs with mild to moderate dehydration.

However, it is important to note that the study looked at using the electrolyte solution in conjunction with other treatments and monitoring in a veterinary setting. It does not mean that electrolyte solutions are a substitute for veterinary care in cases of dehydration due to dog diarrhea with blood.

How can you prevent dehydration in dogs?

Sometimes dehydration is unavoidable when a dog is sick. But there are still some steps you can take to prevent dehydration in your dog and encourage hydration in general.

• Provide your dog access to fresh clean water in a bowl he or she likes to drink from (as discussed above).
• Avoid putting food and water bowls in the corner. Not being able to see potential threats while eating or drinking can make some dogs anxious.
• Have multiple water bowls around the house and freshen the water in them frequently.
• Bring water with you when taking your dog to the park, on a hike, or other places. It can be helpful to keep a collapsible water bowl and a bottle of water in the car so you are always prepared.
• Intentionally stop for water breaks during activities. Dogs may be having too much fun running and playing to realize they are thirsty or overheated until it is too late, so it is up to you to enforce break times.
• Pay attention to how much water your dog is drinking. As a general rule of thumb, dogs need about one ounce of water per pound of body weight over a 24-hour period. However, this can vary depending on the health status of the dog, the weather, how active the dog is, and other factors.
• Ensure your dog is up to date on vaccinations to prevent infections like Parvo.
• Have your vet run fecal tests for dogs during preventive care visits and work with your vet to create a parasite prevention program for your pup.
• Carefully monitor your dog’s health and behavior and promptly report any changes to your veterinarian. The sooner you find and fix the problem, the less time the dog has to get dehydrated.

Hydration matters

Dehydration can be dangerous for dogs, especially when it becomes moderate or severe. If you notice your dog has sticky gums, sunken eyes, skin that stays tented, thick ropy drool, pale gums, or other signs of dehydration, contact your veterinarian immediately. The sooner you can get help for your dehydrated dog, the better.

Plus, remember that in general it is important to ensure your dog has access to fresh, clean water, and to take steps to encourage him or her to drink it. Your dog may not have a favorite Yeti or Stanley cup that goes everywhere with him or her, but he or she can still enjoy (and benefit from) staying well hydrated!

How do you help your dog stay hydrated?

Please comment below.