Pruritus (Itchiness) in Dogs


Overview of Pruritus (Itchiness) in Dogs

If your dog spends a large portion of his time scratching, he may have a condition known as pruritus, or itching, an unpleasant sensation that causes your dog to scratch or bite at himself. It is caused by chemical reactions that occur in the skin and stimulate the nerves, causing the brain to feel the itch. In fact, the act of scratching itself may stimulate these inflammatory reactions in the skin and make the condition worse. Any skin condition that causes inflammation can cause pruritus.

How pruritus affects your dog’s health depends on the degree of the pruritus. Mild pruritus may hardly have any effect at all. However, severe pruritus leads to intense scratching, which may result in painful skin lesions that may become infected. Your dog will often whimper or cry out and may have trouble sleeping.

Every dog has a threshold of pruritus or an “itch threshold.” This is the point where all of the sources of itching finally add up to enough irritation to cause the irresistible urge to scratch. Scratching begins when the stimulation exceeds that threshold. For example, a dog with a mild allergy to house dust mites may be below the threshold but may begin to scratch severely when he becomes infested with fleas.

Pruritus is associated with other skin diseases, including secondary bacterial skin infections (pyoderma) and secondary yeast infections. But it is the main symptom of skin conditions like allergies and skin parasites.

What To Watch For

  • Scratching or biting. If this continues beyond one day and leads to lesions such as hair loss, reddening of the skin and obvious pain or discomfort, have your dog evaluated by your veterinarian.
  • Chronic licking of the feet is also a symptom of pruritus.
  • Diagnosis of Pruritus in Dogs

    Diagnostic tests may be needed to determine the cause of the pruritus. Your veterinarian will probably do the following:

  • A complete and thorough medical history
  • A thorough physical examination
  • Skin scrapings to rule out mange mites and other parasites
  • Fungal cultures of hair to rule out dermatophytes (ringworm)

    Treatment of Pruritus in Dogs

    The key to relief from pruritus is to identify and treat the underlying cause. Pruritus may be temporarily relieved with medication but the itching often recurs after the medication is finished. Temporary relief may come from the following:

  • Antihistamines
  • Fatty acid supplements
  • Soothing shampoos
  • Corticosteroids
  • Home Care

    Administer all veterinary prescribed medication as instructed by your veterinarian. Consult with your veterinarian to establish a complete flea control program.

    Keep your dog’s coat clean and brushed free of mats.

    For more tips – go to Home Care of the Itching Dog.

    In-depth Information on Pruritus (Itchiness) in Dogs

    Related Diseases

    Many skin diseases can cause or can contribute to pruritus. Every dog has a threshold of pruritus. When the nerves of the skin are stimulated by mediators of inflammation to a level below that threshold, the dog will not scratch. Scratching begins when the stimulation exceeds that threshold. It is common to see dogs with two or more skin conditions that cause pruritus concurrently. For example, a dog with a mild allergy to house dust mites may be below the threshold but may begin to scratch severely when he becomes infested with fleas.

    Allergic Skin Diseases

  • Flea allergy is the most common allergic skin disease in the United States. Dogs with flea allergy tend to scratch their back ends leading to lesions on the rump, hind legs, tail and belly. Since it takes just one flea to make the dog react, the presence of fleas on the dog may be minimal to absent.
  • Atopy is a reaction to airborne allergens such as pollens, house dust, house dust mites and molds. Dogs with atopy tend to scratch their ears and face and tend to chew and lick at their feet. The condition is often worse during summer months when pollen and mold levels are increased.
  • Food allergy is a reaction to one or more ingredients in their food. These dogs tend to scratch in the same places as those with atopy.
  • Insect allergies (insect bite hypersensitivity) are less common than other allergies. Lesions are evident in areas where insects such as mosquitoes are likely to bite (bridge of nose, ears).
  • Contact allergy is a reaction to an irritant that touches the skin, often the belly or chest. Allergies of this type are rare.
  • Parasitic Skin Diseases


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