8 Causes of Sudden Weight Loss in Dogs

Sudden weight loss in dogs may signal serious medical conditions and should be reported to the vet. This weight loss in dogs may be caused by:

  • Diabetes
  • Tapeworm
  • Liver Disease
  • Addison's Disease
  • Thyroid Problems
  • Mouth Lesions
  • Dental Problems
  • Pregnancy

When a dog is losing weight, he burns more calories than he consumes. If your dog loses more than 10% of his total weight, this should be a reason for worry.

1. Diabetes

Diabetes is caused by insulin deficit or the incapacity of the body to absorb the sugar from the blood.

Diabetes will cause the dog to have increased appetite, but despite this, he will still lose a lot of weight.

Senior and obese dogs are more prone to developing diabetes; however diabetes may be a genetic disease.

2. Tapeworm

A dog with parasites may lose weight. Dogs with tapeworms are particularly exposed to weight loss. The tapeworm resides in the dog’s intestine and feeds on the food consumed by the dog; consequently, the dog is deprived by essential nutrients and will get thinner.

3. Liver Disease

The liver processes sugars and carbs needed by the body; if the dog has liver disease, the liver will not be able to provide these essential nutrients. The body will consume the fat deposits or muscle tissues.

The dog will also display symptoms such as frequent urination, abdominal pain, jaundice, pale feces and orange urine.

A change in diet is important in managing liver disease. If the disease is caused by toxins, these must be removed from the dog’s environment. The vet may also prescribe additional medication.

4. Addison’s Disease

Addison’s disease is an adrenal insufficiency. The dog has a steroid hormone deficit and will be signaled by vomiting, diarrhea, fatigue, low blood pressure or fever.

The pet will also lose weight.

5. Thyroid Problems

Thyroid problems may lead to hormonal imbalance and to a speeding up of the metabolism. In this case, the dog will lose weight. Thyroid problems may be managed, but need to be detected first.

6. Mouth Lesions

If a dog has mouth lesions, eating will be painful, so he will refrain from eating. Go to the vet to detect any injuries or lesions that are present in the mouth of the throat of the dog.

7. Dental Problems

If your pet has a dental abscess he will avoid eating. The vet will administer antibiotics and will determine if the tooth should be removed.

8. Pregnancy

A pregnant dog may lose weight in the first stage of the pregnancy as she lacks appetite due to nausea. This is not a cause for worry, as the dog will soon gain back the weight.

Sudden weight loss is often accompanied by other symptoms such as poor muscle function, dull coat, dry skin, diarrhea, vomiting, lethargy or depression.

Weight loss may be due to a lack of appetite which may be caused by anxiety.

Other causes of weight loss may include neuromuscular diseases, poor digestion, cancer or heart disease.

The treatment depends on the cause of the weight loss. In some cases, prescription diet will be recommended.