Health & Medical

Ask a Vet: What’s Causing the Rashes and Pimples on My Dog?

Why does my dog have rashes and pimples? | Vanillapup

Q: My 16-month old dog has rashes on his stomach and pimple-like spots around his neck and armpits. He has been licking his stomach recently. An allergy test revealed that he is allergic to various food and environmental allergens. I’ve changed his diet, but what else can I do?

Skin rash and infections can be due to a variety of causes. They include bacterial or yeast infections, ringworm, or mites, such as Demodex or scabies.


These infections and itching require specific topical and/or oral treatment to manage. Bacterial and yeast infections are almost always secondary to an underlying cause, with allergies being common in a younger dog like yours.

To manage the itch, there are various therapies that can help. There are cortisone-based topical sprays (such as Cortavance spray) that are safe for long-term use, and oral therapies like antihistamines and corticosteroids.

There is also a new oral therapy called Apoquel, a non-steroid alternative for managing itch. Only your vet can prescribe these therapies after an updated examination and assessment.

Nonetheless, it is always important to manage the primary cause of the allergies, which would reduce or sometimes eliminate the reliance on medications.

Allergy tests reliability

There are various versions of allergy tests available in the market. However, the only one that has sound veterinary evidence of consistency is an IgE antibody titer test.

It measures the level of antibodies produced specifically against various environmental allergens, such as house dust mites, fleas, and weed, tree and grass pollens.


If the test shows that your dog has positive antibody levels to one or more of these environmental allergens, and other allergies have been ruled out, you can consider long-term immunotherapy to manage the allergy.

This involves gradually exposing your dog to the offending allergens, either via injections under the skin, or sprays in the mouth. This would increasingly desensitize the immune system to the allergens.

While some pets require immunotherapy for at least nine to 12 months, some need it for life to keep the allergy under control.

Food elimination diet

Although some laboratories offer a similar titer test for food allergens, the general consensus is that there is
poor consistency in the accuracy of these results for food allergens.

Hence, the only reliable way to diagnose and manage food allergies is via a vet-formulated elimination diet food trial.

These diets should contain a protein that your dog has never come across before. All the other ingredients in the diet should only be included to keep the diet nutritionally complete and balanced.

If possible, choose a prescription hypoallergenic diet, which contains a hydrolysed form of the original protein. It is less likely to trigger an allergy response.

Do avoid hypoallergenic commercial diets from shops as they may be ineffective due to trace contaminant ingredients from other batches of food. While those traces may be minimal and acceptable for most dogs, it could be enough to cause problems in allergic dogs.

In the same vein, it is also important that other food is not fed at all during the trial (including treats, supplements, and consumable chew toys). That is because it would be difficult to determine whether the response or lack thereof is due to the hypoallergenic diet, other ingredients fed, or other causes, such as environmental allergens.

Lastly, you must keep up with the diet for two to three months to fully evaluate your dog’s response to the diet trial.

Lifelong management

Management of chronic skin allergies is usually lifelong and requires a strong partnership between you and
your vet.

Prepare yourself for flare-ups that may occur even with the best management. The goal is to minimise the frequency and severity of the flare-ups and to optimise your dog’s quality of life.

Photo credit: Lansun via / CC BY-NC-ND

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Dr. Brian Loon
Principal Veterinary Surgeon at Amber Vet
BSc. BVMS (Hons) (Murdoch), Certificate Veterinary Acupuncture (IVAS)

Dr. Brian Loon graduated from Murdoch University, Western Australia in 2007 and has since been practising as a small animal veterinarian in Singapore. His areas of special interest include diagnostic ultrasonography, endoscopy, and minimally invasive (keyhole) surgery (laparoscopy).

He is also certified in Veterinary Acupuncture with the International Veterinary Acupuncture Society (IVAS) and a certified and registered member of PennHIP, an internationally known modality for diagnosing hip dysplasia in cats and dogs.
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