Demodex brevis are tiny mites that live in the oil glands of hair follicles (especially our eyelashes and nipples) and are usually completely harmless causing no symptoms. However, if the numbers increase they can lead to symptoms such as:
This can cause or aggravate blepharitis, ocular rosacea, meibomian gland dysfunction and chalazia (blocked eyelid glands). A Demodex infestation is an often overlooked cause of eye inflammation which could be the root of tougher blepharitis cases.
Demodex mites can be treated using special foams or wipes that contain tea-tree (melaleuca) oil. As a result, some people find that their blepharitis and dry, sore eyes improve too.
The problem with tea-tree oil is that is can be irritating to the skin and eyes, especially in the concentrations need to kill Demodex mites. Most commercially available products have concentrations of less than 1%.
Research has shown that the active ingredient in tea-tree oil that actually kills Demodex mites is 4-terpineol (or terpinen-4-ol). As a result, there are now several products available that contain this extract which can be at a higher concentration (typically 2.5%-5%).
This video from Cliradex is a great outline of Demodex, its symptoms and treatment.
You need to use the tea-tree oil/4-terpineol based products twice a day for 4-6 weeks to ensure all the mites are killed.
After use you may experience mild stinging or tingling on the skin. This usually settles quickly and becomes less noticeable as the days go by.