Pets Are Important Too

Common Causes of Lethargy and Weakness in Dogs

by Aurore Fontai

Dogs can get sick just like humans; however, it can be hard to tell how sick a dog is in some cases because they don't talk. As a dog owner, you are the best judge of how your dog feels. If you sense something is not right, you should take your dog to an animal hospital for treatment. If your dog appears very weak and lethargic, and this is not how your dog normally acts, you may want to find out what is causing it to feel this way. Here are a few of the common causes of lethargy and weakness in dogs.

Allergic Reactions

Dogs can have allergic reactions to things in some cases, and an allergic reaction to something your dog consumed could cause lethargy and weakness. Medication you just started giving your dog is one option. If you recently started a new medication, make sure you tell your vet about this when you take the dog to an animal hospital.

If you did not give your dog any new medication, is it possible that your dog ate something it shouldn't have? For example, if your dog ate food that contains ingredients it was allergic to, that could have caused a reaction. Your dog may have also eaten a household cleaner, weeds, or other things that may have caused the reaction.

Vets often treat allergic reactions with antihistamines or corticosteroids; however, it can be hard to tell if this is the cause of your dog's illness.


An infection can also cause symptoms of lethargy and weakness, and your vet will be able to test your dog for common infections. Some examples of common dog infections include heartworms, parvovirus, and distemper. You can prevent these infections by properly vaccinating your dog each year; however, if your dog did not get all the necessary vaccinations, it could easily contract one of these infections.

Most infections can be treated with antibiotics if they are detected early. If they are not detected at an early stage and treated properly, they can lead to death. This is why it's important to take your dog to a vet if you suspect any type of problem that could be caused by an infection.

Chronic Health Problems

If the lethargy and other symptoms are not a result of an allergic reaction or an infection, there is a chance your dog may have some type of chronic health problem that has not been diagnosed yet. If this is the case, you will need to have a vet run tests on the dog to find out. Many chronic health issues in dogs can be treated, but the results will depend on the diagnosis, the severity of the condition, and the overall health and age of the dog.

One chronic health problem some dogs acquire is diabetes. Your vet can find this out by testing the dog's blood and urine. If your dog tests positive for diabetes, you may need to change its diet, help it lose weight, and give it more time for exercise. In addition, you may also need to give your dog insulin shots to help it control its blood-glucose levels.

A second chronic health problem that can lead to lethargy is heart disease. Heart disease can affect a dog just like it does a person, but it can be treated if detected early. Treatment often includes changing the dog's diet and helping it lose weight. There are also medications designed to help a dog's heart work properly.

Dogs can get sick for many reasons, but you will never know why your dog is sick unless you take it to a veterinarian's clinic. To learn more, contact an animal hospital today.