5 Reasons Your Dog is Itching and Throwing Up

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Itching and vomiting are common symptoms exhibited by sick dogs. When separate from each other, these symptoms can indicate a wide array of health problems. However, when the two symptoms occur at the same time, the field of possible causes narrows.

If your dog is exhibiting itching or vomiting or the two symptoms in combination, you should take your pet to a veterinarian for examination and diagnosis. Among the common causes of severe itching and vomiting in dogs are parasites, allergens, seasonal allergies, fish poisoning, or skin cancer. If the skin irritation or dermatitis is extreme, a veterinary dermatologist might be required.


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1. Tapeworms in dogs

Tapeworms are a common parasite in dogs and can grow to be as long as 2 feet in length. They are made up of small segments that sometimes separate from the longer parasite and appear in your dog's stool, looking like a piece of rice. There are various types of tapeworms, but the type most common in dogs is contracted when the dog eats an infected flea.


In addition to seeing the segment of the tapeworm in your dog's stool or around their anus, you might notice your dog biting or scratching at their anus or see them dragging their rump across the floor. If a dog has a lot of worms, sometimes the worms back up from the intestines to the stomach and then the dog will vomit. If this is the case, there will likely be a tapeworm in the vomit.


Treatment for tapeworms is a simple deworming pill your veterinarian can provide. You may also want to examine your flea control measures and ensure they are adequate. Note that some dog heartworm preventatives also contain dewormer for tapeworms in dogs.

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2. Fleas and flea allergy in dogs

While fleas are a torment to nearly all dogs, some canines have such severe flea allergies that a single bite or exposure to flea saliva can cause allergy symptoms that include vomiting and itching. However, vomiting due to a flea allergy is not common.


Itchiness thanks to fleas can be intense, and a dog might scratch or chew relentlessly, leading to large amounts of hair loss. You might even notice open sores or scabs on the itchy skin. The most common area on which you're likely to see these irritating insect bites are just in front of the dog's tail on their back.



Strict flea control is especially important to dogs with flea allergies. A DVM can also give your pet an injection to ease their discomfort. Occasional medicated shampoo baths can also help. Skin testing can be done to test for flea allergy, as well as environmental allergies like dust mites.


3. Canine food allergies

Like humans, some dogs have severe allergic reactions to certain dog foods or dog food ingredients. The primary symptom of food allergies in dogs is severe itching; skin issues are usually the only food allergy side effect. However, when a dog also has digestive issues, vomiting and diarrhea are possible.


Canines commonly develop allergies to proteins, such as beef, pork, chicken, turkey, and dairy products‌.‌ Diagnosis and determination of what food ingredient is causing your dog's allergies are usually done through a prescribed hypoallergenic diet. The dog is fed a special diet exclusively for eight to 12 weeks or longer to conduct the test. Blood tests aren't a reliable way to determine food allergy in pets.


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4. Salmon poisoning in dogs

Salmon poisoning disease has been reported on the Western coast of the United States. This potentially life-threatening illness is caused by consuming undercooked fish that contains a bacterial-infected parasitic flatworm. Humans, dogs, and other animals are susceptible to becoming sick if they eat trout, salmon, or Pacific giant salamanders that are infected with a specific parasite containing the microorganism Neorickettsia helminthoeca.


In addition to vomiting and itching, symptoms of salmon poisoning disease include the following:

  • Lack of appetite
  • Fever and diarrhea
  • Weakness
  • Swollen lymph nodes
  • Difficulty breathing or panting
  • Increased heart rate
  • Dehydration

Symptoms usually begin five to seven days after eating the fish, but signs of contamination can be delayed by as long as 33 days. If not treated immediately, death occurs in 90 percent of cases after seven to 10 days. Treatment includes sulfonamides and supportive therapy to maintain hydration, electrolyte balances, nutrition, and control of diarrhea to regain pet health.

5. Mast cell tumor in dogs

Mast cell tumor is the most common type of skin tumor cancer in dogs. In addition to causing itching and vomiting, symptoms a dog with a mast cell tumor might exhibit include the following:

  • A visible tumor
  • Loss of appetite
  • Bloody vomit
  • Diarrhea
  • Gastrointestinal upset
  • Abdominal pain
  • Dark or black feces
  • Lethargy
  • Various bleeding disorders

Note that it's not likely a dog will have all these symptoms, but any combination is possible.

Treatment for mast cell tumors in dogs includes surgically removing the tumor if possible and/or radiation and chemotherapy. However, sometimes the only treatment is palliative and not designed to extend the dog's life. The over-the-counter antihistamine Benadryl is often prescribed to dogs with MCTs.

The bottom line

Both itching and vomiting can be cause for concern for pet owners, but itching and vomiting together definitely merit further investigation, likely by a veterinarian. If your dog is both itching and vomiting repeatedly, it could mean they have any of the following underlying causes: tapeworm, fleas, food allergies, salmon poisoning disease, or a mast cell tumor.



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