Health Topics  >  Skin and Coat  > Itching and Scratching

Possible causes of why your dog is itching and scratching so much

Just like with people, there are many things that could be causing the itchiness and scratching, so try to pay close attention to their skin for any signs of self trauma or irritation, including hot spots, hair loss, matting, discharge, crusting or scabs. Where on the body are they scratching? Check the area for wounds, infections, bumps and bites, dryness or oiliness.

Depending on where your dog is scratching or itching, it can help explain what the underlying cause is. For example, food allergies tend to cause itching in the ‘ears and rears’ (e.g. around the head and bum area), and often the paws.

Environmental allergies often cause itchy paws and an itchy belly (but can cause itchiness anywhere). Fleas target the base of the tail and around the neck. 

If you don’t see any wounds or other signs of self-trauma from the itching, scratching and licking, then your best bet is to check for fleas using the White Paper Test. Here’s how: 


Instructions for the White Paper Test for Fleas

  1. Comb your dog’s fur around the base of the tail and neck area with a fine-toothed comb (some pet combs are made specifically for catching fleas).
  2. Take the fluff/fur that exfoliates and place it on something white (e.g. paper towel). Wet the fur and the paper towel. 
  3. If anything that looks like dirt disintegrates and forms a rusty-red color, this is most likely flea poop. This is the tell-tale sign your dog has fleas and is something you should see your vet to treat.


Pet store or over-the-counter flea treatments are limited in their efficacy, and not effective at getting rid of the fleas in your house (which is often 90% of the problem and would result in your dog getting fleas again). A veterinarian-prescribed flea treatment is your best bet to an effective solution.

Sometimes scratching, chewing and licking are responses to pain rather than itchiness, especially if it’s around the paws or bum area. Check for pieces of rock, sticks or etc stuck to your dog’s paws or fur. 

Although not a comprehensive list, the most commonly seen causes of itching and scratching seen in dogs are:


Allergies (Fleas, Food, Environment)

Allergies are the most common cause of itching and scratching that vets see. The three most common types of allergies in dogs are:

  • Food allergies: a major cause of skin issues is a dog’s diet. Many dogs have sensitivities to the protein or meat source in their food.
  • Environmental allergies (contact dermatitis): usually a seasonal pattern is observed, and tends to be worse during Spring, Summer and Fall.
  • Flea allergies: a more severe reaction to a flea bite where a dog develops a wet, oozy skin infection.
Flea dirt in dogs. Use the White Paper Test to confirm. (Source: Wikipedia)

Pro Tip: Look out for your dog rubbing the affected eye(s) with a paw or on the ground. They are trying to relieve the pain.

Dry Skin

This is more common in places with cold winter weather. Part your dog’s fur or hair and check for dandruff flakes or small scabs or if the skin itself is peeling or cracked. This can also be an early sign of an underlying allergy.

Needs a Bath!

Dogs that have been swimming in freshwater contaminated with irritating bacteria or chemicals, or salt water, will often get itchy if they aren’t rinsed shortly after swimming.

Bacterial or Fungal Skin Infections

Any cause of abrasion or trauma to the skin can lead to secondary bacterial or fungal overgrowth and infections. These are usually itchy and cause dry skin, little red or white bumps, scabs or crusts and balding.

Skin Parasites (Fleas, Mites)

A common cause of sudden itchiness are fleas, ticks, mites and black fly bites, especially if a dog is not on a good preventative parasite treatment.

Some can be visible to the naked eye (see White Paper Test above for fleas), while some are microscopic and just look like a rash. You will need to see your veterinarian to check for these.

Ear Infection

Dogs often scratch their ears, but it may be a sign of something more serious when you notice them scratching their ears more frequently or forcefully. Check both of your dog’s ears for redness, swelling, a bad smell, brown discharge or residue.

Ear infections often accompany allergies and can help determine the cause of the itchiness. Ears also get inflamed and itchy from an underlying allergy even without an infection present.  

A possible case of ear infection.

Stress, Boredom or Anxiety

Too much of any of these can lead to obsessive-compulsive disorder, so it’s important that dogs have regular exercise, social interactions and mental stimulation.

Certain Systemic Diseases

Hyperadrenocorticism (Cushing’s disease), hypothyroidism, liver disease, auto-immune diseases, diabetes mellitus, and other more rare conditions can cause a variety of skin lesions that may be noticed as itchy skin or a rash.

Fortunately, these diseases will often have other signs or symptoms that can identify and differentiate them from other skin issues.


A swelling on your dog’s skin, formed in response to a bite or puncture wound. These can look like a small little scab or can be a large fluid filled swelling.