When an owner brings his dog to a veterinary clinic because it has been scratching, licking, biting and rubbing at its skin and has developed skin redness, rashes, sores and patchy hair loss, most veterinarians will follow a fairly routine initial evaluation. The veterinarian will take a thorough history from the dog’s owner about its overall health history, vaccination status, symptoms or clinical signs (including when they started or were first noticed and whether they have waxed and waned, gotten worse or stayed about the same), history of travel to areas outside its normal living environment and whether any other pets in the household are showing similar signs. The veterinarian may also want to know whether the dog has had any recent dietary changes, among other things. After taking the history, the vet will perform a comprehensive physical examination of the animal from the tip of its nose to the tip of its tail, paying particular attention to all obviously abnormal areas of the dog’s coat and skin. Many times, the initial database will also include taking and analyzing blood and urine samples, which can provide a great deal of helpful diagnostic information.
Based on the results of the initial evaluation, the doctor probably will take a number of skin samples from different affected areas. The best samples are taken from areas with oozing sores, puss-filled papules and/or thick crusting. Skin samples can be gathered with sterile swabs, impression smears or deep skin scrapings. Swab samples are taken by carefully dabbing a sterile swab into a sore or area of hair loss and rolling the swab onto a clean glass slide. Impression smears are taken by pressing a glass slide directly onto the skin in hopes of picking up mites or other abnormal organisms. Deep skin scrapings involve squeezing the skin to push mites up from the hair follicles and deeper skin layers and then gently scraping that area with a sterile scalpel blade just until there is mild bleeding. The cells, mites and other debris on the blade will be spread as thinly as possible onto a glass slide. Skin samples by any of these methods should be taken from at least 3 separate sites, and preferably more. The slides will be examined under a microscope, which can easily be done at most local veterinary hospitals. Samples can also be sent to an outside pathology laboratory for more detailed assessment. Sometimes, stool samples will also be evaluated. In severe cases or cases where these sampling methods do not identify the cause of the dog’s discomfort, the veterinarian may recommend taking skin biopsies; this involves cutting out small pieces of tissue from several different areas and sending them to a laboratory for further evaluation. Most dogs need local sedation for skin biopsy procedures, to ensure their cooperation and comfort.
Owners of dogs that have been diagnosed with any form of mange should closely follow the treatment plan recommended by their veterinarian.