Why Is My Dog Constantly Scratching and Biting Himself?

A dog who is itching a lot is uncomfortable. The constant scratching is annoying – for both of you! Tracking down the cause is the only way to halt the itch.


A dog who constantly scratches himself can drive you crazy. And it certainly isn’t good for the dog either, as all that itchiness can result in secondary skin infections. Rather than dumping a bottle of flea powder on him and thinking you’re done, consider the many different things can cause itchiness in dogs:

  • Arthritis
  • Dry skin
  • Environmental allergies
  • Fleas
  • Food allergies
  • Mites or mange
  • Skin infections

Resolving this itchy-skin problem is not easy, but it can be done. If all else fails, involve your veterinarian. Waiting until the intensity of the itching worsens, makes treatment more expensive and your dog suffers longer.

Fleas Are No. 1

While we stand by our recommendation not to just reach for flea powder without a reason, the fact is that the first thing to rule out if your dog is constantly scratching and biting at himself is fleas. These tiny parasites cause itchy bites, especially around a dog’s rump and back. Use a flea comb to search for freeloaders in your dog’s coat.

And, although you pay a lot for flea-and-tick preventatives – and apply them according to package instructions – these products can fail. Application errors, wrong-sized doses, bad timing of treatments, and resistance to the product can all occur.

Yes, fleas are becoming resistant to some products. Fortunately, it tends to be a local resistance, so that why it’s a good idea to find out which product your veterinarian likes rather than just buying an off-brand product that’s on sale. The vets know what’s working and what isn’t. And try to choose a product that is effective against fleas, ticks, and mites (mites cause mange).

Once fleas have been found, you must treat all pets in the household for at least three months with a good flea preventive. Don’t forget to treat cats too, but with a cat-safe product.

This will ensure that you eradicate the infestation and cover any flea eggs and larvae that are hiding in your carpeting and furniture. Many people treat the carpets, too, wash bedding, and so on. This doesn’t hurt, and you must remember that flea eggs are very hardy, so a thorough cleaning can help.

If your dog is one of the unlucky ones with flea-allergy dermatitis, even one flea bite will cause her to break out in an itchy rash. She and any other pets in the house will need to be kept on a flea preventive year-round to protect your dog and prevent itching.

Other Causes of Dogs Scratching a Lot

Dry Skin: No fleas? Check the condition of the dog’s skin. Skin that is pale and healthy looking but has a lot of flakey white dandruff may simply be too dry, which can be itchy. Try adding a fish-oil supplement to support your dog’s skin and coat health and/or using a humidifier in the house may help.

New Topical Product: Be mindful of any new shampoo products, sprays, or other things you put on your dog’s coat. Some of them can dry the skin, and some can cause allergic reactions in some dogs. There are no true “hypoallergenic” products.

Infection: Skin that is red, inflamed, and oozy or crusty indicates an infection. Your dog will need to go to the veterinarian to determine the cause of the infection and the best treatment.

Arthritis: Chewing and licking around joints can be a sign of arthritis pain. These dogs often have reddish staining in the spot from their saliva. Your veterinarian can diagnose arthritis and start your dog on joint supplements and pain medication.

Allergies: Allergies are a diagnostic challenge. Your veterinarian will ask lots of questions about your dog’s environment, lifestyle, what time(s) of year the itchiness shows up, and what she eats both for her main diet and as treats. From there the veterinarian will recommend diagnostics and other strategies to try to rule out or identify antigens that are causing your dog’s troubles.

Finally, a few illnesses can make your dog itch, too, including thyroid disorders, diabetes, and liver disease. Don’t forget to tell your vet if the itchiness is new, especially if the dog is receiving a new medication.

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Kate Basedow, LVT is a long-time dog enthusiast. She grew up training and showing dogs, and is active in a variety of dog sports. She earned her Bachelors Degree in English from Cornell University in 2013, and became a licensed veterinary technician in New York in 2017. She has been writing professionally about dogs for most of her life, and has earned multiple awards from the Dog Writers' Association of America. Kate currently has three dogs at home, as well as a cat, two zebra finches, and six ducks.