Demodex Mites: What Are They?
What are Demodex mites?
Demodex mites are micro-organisms that naturally live in the hair follicles of mammals. There are two species of these mites that affect humans: Demodex Folliculorum and Demodex Brevis. Demodex Folliculorum are found in smaller hair follicles, and are usually found only on the face, 
whereas Demodex Brevis are found in the oil glands near hair follicles. While still more prominent on the face, Demodex Brevis can also be found on other parts of the body. Collectively, these two species are referred to just as Demodex.
While the thought of having mites living on your face can be repugnant, they actually can be useful as long as the population does not get out of control. Usually, the populations are naturally kept under control with regular washing, however, we aren’t all taught to “shampoo” our eyelashes, and thus populations can quickly grow out of control in this area.
Demodex mites are able to alter the human immune response to inhabit the skin without triggering an immune system attack, thereby ensuring their survival and thriving on the skin.
Interestingly, adult demodex mites are classified as arachnids as they have eight legs [3].
How do you get demodex?
Mites can be transferred by direct skin to skin contact. Humans are not born with demodex mites and children are rarely affected as they do not produce as much sebum as adults.
Sharing makeup also plays a role in transmission as demodex can survive on cosmetics anywhere from several hours to several days [3].
How do I tell if I have demodex?
It is estimated that 23%-100% of healthy adults have demodex [3]. While these mites typically coexist with humans without complications, an overpopulation can lead to a myriad of symptoms.
These symptoms may include itchiness, foreign body sensation, burning, debris on the eyelashes and cornea, intermittent blurry vision, swollen eyelids, chronic inflammation, recurring chalazions, sticky discharge and even temporarily or permanent eyelash loss.
Since the demodex mites spend the daylight hours under the skin at the very base of the lashes or oil glands, and due to their microscopic size, it’s hard to determine whether or not you have an overpopulation on your own. During an examination with an optometrist, the evidence of too many mites is usually what is noted; rarely do we see the mite itself. Demodex leaves a very distinct type of debris on the lashes. Referred to as “cylindrical dandruff”, this debris coats the lash all the way around, almost like a cuff. This substance can be a bit waxy, which can make it slightly difficult to remove.
However, changes in our skin as a result of aging, rosacea, immunosuppressants, hormone imbalances, obesity, and hygiene routines contribute to populations growing out of control.
How do I get rid of demodex?
As stated previously, demodex mites are a part of our natural ecosystem, making complete eradication virtually impossible. The objective is to create an inhospitable environment in the eyelash area to prevent population surges that result in symptoms.
To accomplish this, thorough cleansing of the lash bases is necessary to eliminate bacteria, debris, buildup, and shed skin cells, which serve as food sources for demodex mites. The most effective way we have in-office to remove the build up from demodex is a Lid Debridement.
Lid debridements can be likened to an exfoliation of the eyelids, specifically the base of the eyelashes. Using customized products, the eye lashes, meibomian gland openings and lid margins are cleaned and exfoliated. It’s crucial to follow up with an at-home lid hygiene routine afterwards as the debridement procedure is unable to reach the demodex mites deeply embedded in the skin. Without ongoing care, debris can quickly accumulate on the eyelashes again, potentially leading to uncontrolled population growth in as soon as a week. In severe cases, Intense Pulsed Light (IPL) treatments may also be recommended to target the presence of inflammation and bacteria.
We recommend using lid wipes containing tea tree oil, such as I-Lid n’ Lash Plus for at least two months after undergoing a debridement. After that time, switching to lid wipes without tea tree oil may be considered. Although commonly called “lid wipes,” these are primarily designed for cleansing the eye lashes. The I-Lid n’ Lash Plus wipes are specially formulated to gently exfoliate and cleanse the delicate eye area safely. It’s important for patients to refrain from concocting their own solutions or wipes, as excessive tea tree oil can be harmful to both the skin and eyes. Demodex mites are also resistant to most antiseptics, making it crucial to use high-quality products that have been thoroughly tested and proven effective [4].
Prior to these products, optometrists advised washing the eyelashes with a mixture of baby shampoo and water. However, further research has found that this method is ineffective and can be irritating. In some instances, using baby shampoo did not reduce the number of demodex on the eyelids; the population remained unchanged or even increased [4].
Prevention & Maintenance
Here are some tips to prevent demodex mite overpopulation and maintain the health of your eyes and surrounding area.
- Routine eye exams: Your optometrist is a vital partner in maintaining eye health. Routine exams go beyond just updating your prescription; they include an assessment of both the internal and external parts of the eye for any potential issues. Early detection is crucial for managing most eye conditions [5].
- Daily eyelid and lash cleansing routine: Developing a daily routine to thoroughly clean the eye area is essential to protecting the eyes from the overgrowth of bacteria, dead skin cells, debris, pollen and demodex mites.
- Replace eye makeup as recommended: Eye makeup should be replaced regularly to avoid accumulation of bacteria and other microorganisms. Liquid eye makeup (mascara, eyeliner and eye shadow cream) should be replaced every three months. Powder eye shadow can last between six and nine months, as long as brushes and applicators are cleaned regularly. Makeup shouldn’t be used with an eye infection, and replaced after an infection occurs. Additionally, makeup should never be shared and should be thoroughly removed before going to sleep.
- Wash bedding and towels regularly: Bacteria, debris, microorganisms, dust, hair and body oils accumulate in bedding, especially in pillows and pillowcases. Generally, pillows should be washed a few times a year depending on the material. Pillow cases and sheets should be cleaned every one to two weeks. Consider using a pillow protector and mattress cover. Bedding may need more frequent washing if there are spills, food consumed in bed, or pets sharing the space.
- Avoid sharing a bed with pets: While having furry companions is delightful, their fur can harbor irritants like allergens, bacteria, parasites, fungi, and viruses. Outdoor cats pose a greater risk of contaminating their owners compared to indoor cats.
References:
[1] Paichitrojjana A. Demodex: The worst enemies are the ones that used to be friends. Dermatol Reports. 2022 Mar 23;14(3):9339. doi: 10.4081/dr.2022.9339. PMID: 36199896; PMCID: PMC9527693.
[2] Rather PA, Hassan I. Human demodex mite: the versatile mite of dermatological importance. Indian J Dermatol. 2014 Jan;59(1):60-6. doi: 10.4103/0019-5154.123498. PMID: 24470662; PMCID: PMC3884930.
[3] Sędzikowska A, Bartosik K, Przydatek-Tyrajska R, Dybicz M. Shared Makeup Cosmetics as a Route of Demodex folliculorum Infections. Acta Parasitol. 2021 Jun;66(2):631-637. doi: 10.1007/s11686-020-00332-w. Epub 2021 Jan 19. PMID: 33462683; PMCID: PMC8166727.
[4] Gao YY, Di Pascuale MA, Li W, Baradaran-Rafii A, Elizondo A, Kuo CL, Raju VK, Tseng SC. In vitro and in vivo killing of ocular Demodex by tea tree oil. Br J Ophthalmol. 2005 Nov;89(11):1468-73. doi: 10.1136/bjo.2005.072363. PMID: 16234455; PMCID: PMC1772908.
[5] (2023, March 29) Eye Exam vs Sight Test. Canadian Association of Optometrists. https://opto.ca/eye-health-library/eye-exam-vs-sight-test
Written and researched by Holly, our Ocular Hygienist