Reasons Your Dog is Itching Despite Medication

Reasons Your Dog is Itching Despite Medication

If your dog has a persistent itch that makes them scratch or chew themselves, a visit to your veterinarian will help narrow down the cause and get them started on a safe and effective anti-itch medication. Sometimes your vet will prescribe multiple medications together to both ease your dog’s itchiness and address the root cause of your dog’s skin condition. But what if you’re still seeing your dog itching after they’ve started an anti-itch medication? Or you notice that they’re itching again when their medication had been previously working well?

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Flare factors that are causing your dog’s itch

There are a few reasons this could be happening — different “flare factors” can increase your dog’s itching despite being on previously-effective medication. A flare factor is a condition that causes dramatic worsening of itching or skin inflammation that was previously under control. These factors include fleas, staph (bacteria) or yeast (fungal) infections, and food allergies. If you’re noticing an increase in your dog’s scratching, they may have developed one or more of these flare factors that are pushing them over their “itch threshold” despite being on anti-itch medication.

  • Fleas. Flea control is crucial to controlling flares of allergic itch. Intermittent exposure to fleas, such as when a pet owner only applies flea preventative when they see fleas or for a few months during the summer, increases the risk of developing flea allergy[1]. Aggressively treating the fleas in these dogs makes controlling their chronic itch much easier, by keeping them below their allergic threshold.
  • Staph or yeast infections. Dogs with atopic dermatitis have increased Staph and yeast on their skin compared to normal dogs, due to a breakdown in their protective skin barrier. Your veterinarians can prescribe oral, injectable and topical medications to treat these conditions.
  • Food allergies. The most common food allergens are animal proteins, and grain-free diets are not likely to be helpful. The best way to determine what food allergies your dog might have is an elimination diet followed by food challenge trials. Mislabeling of over-the-counter dog food is common, even with hypoallergenic ingredients, so a prescription or veterinarian-supervised home-cooked diet is often best.
  • Seasonal allergies. Seasonal spikes in pollen levels can also cause a flare.

The reason for the flare-up in your dog’s scratching needs to be addressed – whether it’s getting back on track with a flea preventative, a prescription treatment for the bacterial or fungal skin infection, or a vet-monitored food trial to determine any food allergies that your dog might have developed. Your dog’s immune system can only handle so much, and a combination of these factors can push your dog over their “itch limit” and can make them uncomfortable.

Proactive treatment for dogs with environmental allergies

Dogs with environmental allergies (known as atopic dermatitis) can benefit greatly from the following proactive treatments and management[2,3]:

  • Control their itch and inflammation with medication.
  • Work with your veterinarian to find the underlying cause of your dog’s itch. Possible causes of itch can be found here.
  • Make sure your dog is on year-round flea control — your veterinarian can recommend the best option for your dog. An oral treatment versus a topical solution may be best because you’ll likely be bathing your dog regularly.
  • Bathe your dog weekly with a medicated shampoo and use anti-itch sprays and/or mousse as recommended by your vet. This will help prevent staph and yeast infections, which are a major flare factor as they weaken your dog’s natural skin barrier and make them more susceptible to allergens.
  • Keep your dog on a hypoallergenic or high fatty acid diet that will support their skin barrier.
  • Consider allergen immunotherapy—either injections under the skin or allergy drops given orally to normalize your dog’s immune response to allergens.
  • Work closely with and stay in touch with your vet (or even a board-certified veterinary dermatologist) to keep flares and other skin problems to a minimum.

By taking some steps to prevent flare factors, your dog’s regular anti-itch medication will work more effectively, and your dog will be more comfortable.

Michele Rosenbaum, VMD, DACVD

Michele Rosenbaum, VMD, DACVD

Born in North-Central NJ, Dr. Rosenbaum received her VMD with honors from the University of Pennsylvania. After 4 years of private small animal practice in northern NJ, she returned to the University of Pennsylvania and completed her residency in Dermatology and Allergy, obtaining board certification from the American College of Veterinary Dermatology, then continued as a Lecturer in dermatology at Penn. She then joined a multi-specialty referral practice in Rochester, New York where she practiced for 10 years before joining Zoetis. Dr. Rosenbaum has lectured extensively and has published articles on a wide variety of dermatology topics. Her areas of particular interest include canine and feline allergic dermatitis and management of recurrent and resistant pyoderma.

  1. Wilkerson MJ et al. The immunopathogenesis of flea allergy dermatitis in dogs. Vet Immunol Immunopathol 2004; 99:179-19
  2. Olivry T, et al. Treatment of canine atopic dermatitis: 2010 clinical practice guidelines from the International Task Force on Canine Atopic Dermatitis. Vet Dermatol. 2010;21:233-248.
  3. Olivry T et al. Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Veterinary Research 2015; 11:210.

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