Diagnosing Mange in Pets
Positive diagnosis of mange, or demodex mites, is based on finding a skin scraping with the mites. Your veterinarian may make a presumptive diagnosis of demodex infection even though mites are not found on a scraping if your pet has all the symptoms.
Skin Scraping Tests
Demodex mites live in hair follicles, so the infection is diagnosed by your veterinarian scraping your pet's skin and looking for the mites in scraped material under a microscope. To increase the likelihood that mites are found, your veterinarian will pinch or squeeze your pet's skin gently before taking the scrapping.
A dull tool, such as the back of a scalpel blade is used to scrape your pet's skin. Because mites are hidden in hair follicles, which are nourished by capillaries, a tiny amount of bleeding occurs if the scraping is deep enough. Finding an occasional mite on a skin scraping is normal, but finding many mites diagnoses an infection—especially if the mites are the immature form, which has six legs. A scraping that does not open some capillaries and bleed a tiny amount is not likely to yield results.
Even with excellent scraping techniques, mites can evade detection, so some veterinarians decide to treat pets even though mites were not found on a scraping.
Other Tests Used to Diagnose Mange
Pets that have positive diagnosis of demodex mites by skin scraping often benefit from several other tests:
- Fecal exams for worms
- Blood tests for heartworm infection
- X-rays for tumors
- Blood tests for kidney and liver function
These tests are helpful because many pets that develop demodex infections have other serious infections or disease. The tests mentioned above help find these problems which can range from cancer and poorly functioning thyroid glands to heartworm infections and intestinal worms. In pets with high white blood counts, veterinarians look for co-existing fungal infections such as blastomycosis or cryptococcosis.