Itchy Dogs and Cats–A 3 Part Series: Part 1

Written by Dr. Angie Ahlstrom

For the next 3 weeks we will be doing a series on the “Itchy Patient.” We will cover different causes of itchiness in dogs and cats and the treatment options for each.

Part 1: Fleas and other Parasites

One of the most common—and easily treatable—causes of itchiness in dogs and cats is fleas. Itchiness from fleas is frequently found on the head and ears and at the tail base; these are difficult areas for cats and dogs to groom, so the fleas can “hide out” here. Your dog or cat may have hair loss or scabs in this area. Because fleas are so small and because animals will try to groom them away, you may not see fleas on your dog or cat. However, you may see “flea dirt”—dark red to black material that the fleas excrete.

To treat fleas, your veterinarian can use a pill that will quickly kill the fleas on your pet; this pill typically lasts for 24-48 hours. Therefore, it is important to also start a flea preventative to keep new fleas from getting on your pet. There are multiple different options for flea preventatives (monthly oral pills, monthly topical ointments, and even collars that can last for up to 8 months), so find one that works best for you and your pet.

**Please use veterinary approved flea products on your animal—certain over the counter flea preventatives can cause severe skin reactions and can even cause neurologic problems such as seizures**


Other causes of itchiness in dogs and cats include mites; these can further be divided into contagious and non-contagious organisms.

Contagious Mites

  1. Sarcoptic mange:
    •  This is a disease of dogs caused by the mite Sarcoptes scabei. Dogs with sarcoptic mange are intensely itchy, frequently keeping their owners up at night. While the mite cannot infest humans, they can make you very itchy if they jump on your skin. Diagnosis requires “scraping” the dog’s skin and looking for mites with a microscope.
    • There are several treatment options for sarcoptic mange. The most common is application of a topical ointment every 2 weeks for at least 3 doses. Another option is weekly lime sulfur “dips”—while rather odorous, this is an effective treatment. Treatment is complete when a second skin scrape reveals no mites.
  1. Ear mites:
    • This is typically a disease in cats caused by the mite Notoedres cynotis. Cats affected with ear mites will have very itchy ears, typically with dark debris that resembles coffee grounds. Diagnosis usually involves looking at a sample of ear debris with a microscope—mites will frequently be found.
    • The most common treatment option for ear mites is a topical ointment applied to the skin between the shoulder blades. This ointment helps treat and prevent ear mites as well as preventing fleas and other parasites.

Non-contagious Mites

  1. Demodex
    • Demodex is a mite that normally lives in the hair follicle without causing any problems. However, in some animals, it can overgrow leading to hairloss and itchiness. Diagnosis is made via a deep skin scrape—this is necessary because the mites live at the base of the hair.
    • Treatment varies based on the severity of the disease as well as the age of the animal. In young animals with very few lesions, topical therapy with an ointment can be effective—these dogs and cats generally respond very well to treatment. In young animals with multiple affected areas as well as in older patients, daily oral medication (ivermectin) or weekly baths with a strong medication are the most common treatment option. In addition, in older animals, frequently there is an underlying illness that has caused the mites to overgrow. Therefore, more diagnostics are run on older patients diagnosed with Demodex.


Come back next week to learn about Food Allergy in dogs and cats.

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