Warning signs: 9 dog illness symptoms and what they mean

Regular vet checkups will create a baseline, so it will be easier for you to spot dog illness symptoms that could signal severe health conditions.

Because dogs can catch illnesses from other dogs, it’s essential to keep an eye on any dog your pup interacts with, whether it’s a dog you know or a lost dog.

As a rule, monitor any changes in your dog’s behavior. For example, if your typically energetic dog is lazy for an afternoon, he might be tired. But if your active, outgoing dog routinely becomes lethargic or if your shy, quiet dog begins barking uncontrollably, the change could be his way of indicating something is wrong. You know your dog best, so if he is doing something different, it is time for a check-up.

Common dog illness symptoms and what they mean: 

Appetite or weight change 

Monitor your dog’s food intake. If your dog starts gaining weight even though you haven’t changed the amount you feed him or how much exercise your dog gets, that can be a warning sign. Dogs that rapidly gain weight for no apparent reason can suffer from an underactive thyroid or Cushing’s Disease, which is caused by the overproduction of cortisol. 

If your dog starts losing weight for no apparent reason or shows little or no interest in eating, that can be a sign of several severe conditions, including cancer, liver problems, and kidney failure. It also could be a sign that your dog is in pain from a condition like arthritis. 

Sometimes dogs will skip meals, but if your dog goes more than 48 hours without eating anything, consult your vet immediately. 

Vomiting

Dogs occasionally vomit. Sometimes it’s because they ate something that upset their tummies. Sometimes it’s because they are nervous.

The key is to watch for changes in behavior. If your dog suddenly starts throwing up after every meal, start by checking your dog’s food. If you haven’t changed what you are feeding him, did you start a new bag? Check to see if the manufacturer has changed any of the ingredients. It’s possible something new is bothering your dog’s digestive system. 

It’s also possible your dog has eaten something he shouldn’t have, like a small toy or a piece of your shoe. In that case, he’s merely trying to get it out of his body.

If your dog starts consistently vomiting, it’s possibly a sign of a more serious health issue including gastric ulcers, viral or parasite infections, bloat, liver or kidney failure, gastrointestinal illnesses, pancreatitis, or even poisoning.

Take your dog to the vet immediately if your dog throws up blood. Don’t wait. Every second could be critical. 

Diarrhea

Similar to vomiting, watch for diarrhea. If your dog occasionally has a loose stool, it could be because he ate something that didn’t agree with him or he could be nervous. 

Watch for repeated bouts of diarrhea, especially if accompanied by vomiting or fever. Then, your dog could have an infection (bacterial, viral, or parasitic), gastrointestinal illnesses, inflammatory bowel disease, hemorrhagic gastroenteritis, parvovirus, or colitis. Diarrhea also can be a sign of cancer, or liver or kidney disease. 

If your dog continues to struggle with diarrhea, consider creating a natural indoor puppy potty to make it easier for you to clean up the mess. 

Increased thirst

Excessive thirst and frequent urination are signs of five serious dog health problems: diabetes, kidney failure, liver disease, leptospirosis, and Cushing’s Disease. Your dog also may have a urinary tract infection or bladder stones.

If your dog drinks a lot of water on a hot day, you don’t need to worry. But if your dog starts drinking more water than usual every day, you may have a problem and should talk to your vet.

Watch for signs your dog is drinking too much. Is your dog asking to go outside more often? Or worse, is your dog starting to have accidents in the house even though he’s long been potty-trained. 

Coughing

Don’t worry about an occasional cough or sniffle. But constant, recurring coughing can be a sign of something serious including: 

Infection: Both kennel cough and canine influenza can cause coughing. If your dog has a bacterial infection, it can be treated with antibiotics. But if a viral infection causes the cough, you’ll need to keep your dog calm so he can rest and recover. 

Heartworm disease: Heartworms are transmitted in larval form by mosquito bites. The larva then migrates to the dog’s heart and lungs where they grow into spaghetti-like adults that can cause fatal heart and lung damage. The best way to protect your dog is to use monthly heartworm preventative. Treatment for heartworm disease is costly and can’t reverse heart and lung damage.

Other causes of coughing include congestive heart failure, mitral valve endocarditis, dilated cardiomyopathy, collapsed trachea, chronic bronchitis, or cancer. 

Hair loss and itchiness

Hair loss or itchiness can be a reaction to stress, food allergies, or bites from fleas, ticks, or mange mites. Shedding also can be a sign your dog isn’t getting the nutrients she needs from her dog food. If your dog’s shampoo irritates her skin, that can cause shedding, too. 

But losing hair also can be a sign of a hormonal imbalance, inflammatory bowel disease, thyroid disease, Cushing’s disease, ringworm, endocrine problems, or infections (fungal, yeast or staph). When in doubt, talk to your vet. 

Runny nose or watery eyes

Severe nasal discharge can be a sign of infection or nasal mites, a weak immune system, pneumonia, and cancer. It also can be a sign of dental disease. 

Epiphora causes overproduction of tears. The condition can be caused when the eyelashes turn in, or the eyelids turn out. It also can be caused by sinus infections, tear duct obstructions, or tumors.  

Stiffness

When dogs begin to show stiffness in movement, most owners blame aging. But watch for signs that your dog is limping, having trouble shifting from sitting to getting up or lying down, or has difficulty navigating stairs. Then, your dog may be suffering from bone or joint issues.

Those can include hip dysplasia, disc disease, ruptured ligaments, or arthritis.

Red or swollen gums

Irritated gums are usually a sign of gingivitis, which can be treated before it becomes a more serious periodontal disease.

The best way to prevent dental problems is to brush your dog’s teeth daily. Dogs experience many of the same problems humans do, including cavities, tooth decay, and gum disease.

Gum disease is so common most dogs show early signs of it by the time they’re three years old, according to the American Kennel Club.

Signs of periodontal or gum disease include bleeding gums, drooling, difficulty chewing, gum recession, bad breath, loose teeth, and pawing at the mouth. Failing to treat gum disease can cause infections that will shorten your dog’s life.

Keep an eye on your dog

You know your dog, so always keep an eye out for changes in their behavior. If you notice dog illness symptoms, consult with your vet. By working with your vet, you’ll be able to develop treatment plans and help you give your dog a long and healthy life. 

Lauretta Williams is one of the co-founders of PawMaw.com, a website dedicated to creating happy endings by reuniting people with their lost pets.

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