Demodex is one of the forms of mange our dogs can develop. Demodex are microscopic mites that cause hair loss, itching, and irritation. Demodex is not considered contagious. Pets that have this issue are genetically suseptible to getting it and should not be bred. Demodex is also more common in puppies. To test for demodex we perform a skin scrape on infected areas and look at it under the microscope where we can actually see the mites. yuck!