Face Mites And Demodex —
Normal Residents, Occasional Trouble

Two species live on human skin. Demodex folliculorum, about 0.3 to 0.4 mm long, sits in hair follicles, including the eyelashes. Demodex brevis, about half as long, lives further down, in the oil glands. Both have eight legs and are far too small to see without a microscope.

They gather where skin is oiliest: the forehead, cheeks, sides of the nose, lashes and ears. Their food is skin cells and gland contents; they are mostly active at night and pull back into the follicle in bright light. They are rarely found in children under five, and become near-universal in adults.

Having them is not a sign of poor hygiene. The useful question is not whether you have face mites, but whether their numbers have outgrown what your skin can tolerate.

Overgrowth is called demodicosis. Studies treat more than about five mites per square centimetre as abnormal, but that count is a guide read alongside how the skin looks, not a test on its own.

It shows up in two main ways. Some people get fine, dry, sandpaper-like scale at the follicle openings. Others get inflamed bumps and pus spots, often around the mouth and eyes, and it can affect one side more than the other. When it follows lowered immunity, local or general, it is called secondary; long-term steroid cream on the face is a recognised local cause.

Other reported contributors include older age, oily skin, heavy occlusive make-up, oil-based cleansers and a damaged skin barrier.

The eyelids

Demodex blepharitis affects the lash line: itchy lid margins, crusting, waxy cuffs of debris around the base of the lashes and sometimes lash loss. It is managed together with an eye doctor.

Mite numbers are consistently higher in rosacea, especially the bumpy, papulopustular form, and they probably add to the inflammation. They are not its root cause: rosacea rests on the skin's own immune and blood-vessel overreaction.

That has a practical consequence. Treating mites can calm the bumps, but it does not close visible vessels, stop flushing or remove triggers such as heat, sun, alcohol and spicy food. Where both are present, a treatment aimed at mites is added to sun protection, barrier care and trigger management, not used instead of them.

Diagnosis starts with the history, including every product and any steroid cream, and an examination. Through a dermatoscope, overgrowth can show fine, spiky white threads at the follicle openings: the tails of the mites. If a count is needed, a slide with a drop of cyanoacrylate glue is pressed onto one square centimetre of skin and the mites it lifts are counted under a microscope; a scraping is the alternative.

The aim is to bring numbers back to normal and settle the inflammation. Getting rid of every mite is neither possible nor needed.

• Topical treatment first. Ivermectin cream has been compared with metronidazole cream in a randomised study in inflammatory rosacea; permethrin, metronidazole and sulfur preparations are other options. The evidence for several agents is limited, so the plan is checked and adjusted rather than fixed.
• Oral treatment is kept for extensive disease or lowered immunity; a tetracycline-class antibiotic may be used where rosacea inflammation is marked, after side effects and interactions are checked.
• Eyelids need lid hygiene and lash-line products under an eye doctor.
• A simpler routine underlies everything: a gentle non-soap cleanser and fewer heavy, oil-based products.

Prescription items need an assessment first, and pregnancy or breastfeeding changes the options. Redness that persists after the mites and inflammation are controlled may then suit vascular laser, which treats vessels, not mites.

• Steroid creams. They blanch the redness for a while, then let mites multiply and the rash spread. Stopping long-term use should be guided by a doctor, because the skin often flares first; perioral dermatitis follows the same pattern.
• Scrubbing. It cannot reach mites inside the follicle and damages an already irritated barrier.
• Stacking acne products. Benzoyl peroxide washes, strong acids and full-strength retinoids tend to sting mite-prone and rosacea-prone skin.
• Internet remedies. Neat tea tree oil, home mite killers and repeated antiseptic washes irritate easily and can blur the diagnosis.

Washing pillowcases and make-up brushes is sensible, but mites are part of your own skin, not something picked up from bedding.