There are 2 described species of human Demodex mites: D. folliculorum found in hair follicles, and D. brevis, found in sebaceous glands. Demodex canis infects dogs but can also be a zoonosis in humans. These little guys can be considered normal fauna of humans and are found in up to 2/3 of elderly individuals. Fortunately most individuals are asymptomatic.
Most labs usually use a simple wet-prep when looking for Demodex mites. In this case, these mites were a fortuitous find on a preparation designed to identify dermatophytic fungi and are probably not the cause of the patient's symptoms.
And now our poem from Blaine Mathison:
Living peacefully down in the sebaceous gland
is the fairest of the mites in all the land
not to be confused with his sarcoptid kin
Demodex doesn’t cause scabies on the skin
but a saprophytic life that’s really quite bland