Do demodex mites causes the skin to be oily?

Yes they do: Demodex mites live in sebaceous glands and are associated with oily skin. They can be treated with an antibiotic but may recur. Other treatments for oily skin and rosacea need to be used. See your dermatologist for ongoing help

Not likely: Demodex mites have been associated with a whole host of skin issues but there exact pathogenicity(disease causing nature) isn't exactly clear. They do subsist off of dead skin and sebum(oil) but it hasn't been suggested that they directly cause oily skin.

Demodex Mites: Demodex mites infect the hail follicles and the sweat glands around. They try to burrow into the sweat glands and causes cylindrical dandruffs. Yes can make the hair oily and sometimes dry. Washing bed coverings in hot water and ironing them, spraying with insecticides helps clear from room. shaving, treating with ocusoft/Tea tree oil. Usually spread by close contact.

NO!!!!: Look up demodex. Most adults and many children carry them. The older you are the more you have. They rarely if ever cause any symptoms. No antibiotics are used for this, but sometimes permethrin cream is used. In case of scabies, they protect their territory and repel scabies mites from the face and scalp. You need to stop the enormous dose of folic acid, take Vitamin B12 instead.