Do Mites in the Pores Cause Rosacea?

Cynthia Bailey, MD|October 4, 2012

The pores on your skin are home to many microscopic inhabitants including bacteria, yeast, and – yesmites. The rosacea puzzle is taking form and microscopic mites may well be playing an important role! The mites are demodex. Mammals have demodex on their skin, us included. Demodex mites live mostly in our pores and oil glands. They prefer the oiliest parts of our face like the "T-zone". They eat skin cells and sebum (skin oil). They're shy; rarely venturing out of the pores where they live, lay their eggs and die. We've known that skin affected by rosacea has a greater numbers of mites in the pores. What we haven’t known is just what the connection is between the mites and rosacea's skin problems. But, the puzzle is starting to take form. Scientific studies connecting mites and rosacea have been popcorning out in medical journals and conferences over the past few years. Researchers are gathering evidence that a bacteria on human demodex mites may trigger a complex cascade of events that lead to the skin problems of rosacea. A paper just published in the August Journal of Medical Microbiology surveyed the scientific literature looking for all of the scientific studies examining the mite/rosacea connection. The authors found a number of papers linking the skin problems of rosacea to the presence of the bacteria on demodex mites. These skin problems include skin barrier fragility (sensitive skin), flushing, permanent "broken" facial capillaries, sebaceous hyperplasia (enlargement of oil glands), and the red rash and pustules of rosacea. There are two bacteria that may be to blame, Bacillus oleronius and Staphylococcus epidermidis. Interestingly, these microbes are sensitive to the antibiotics that we dermatologists have used for years to treat rosacea. It may have been the mite's bacteria that we've been treating all along. Conclusions haven't been reached but it's fascinating, surprising, and just a little creepy. So what are the facts that we do know about demodex mites on our skin?

  • Demodex mites live in the pores on places of the human body where there is a lot of oil (T-zone, chest, ear canal, and groin). Only rarely can they get through the lining of the pore and into the second layer of the skin called the dermis. When they do, they may cause severe inflammation such as large inflammatory pustules (pimples). It may be this entrance into the skin that is responsible for some of the worst inflammatory aspects of rosacea.
  • Demodex mites live for less than 3 weeks and their eggs hatch in less than 3 days.
  • They have to be in a pore to survive; they can’t live outside the pore. They only come out of the pore at night to mate, traveling at most ½ inch away from their home for dating purposes! When done, they scramble back down into their pore to lay their eggs. Click here to see the best (and grossest) pictures that I could find of demodex mites stuffed into human pores head first (which is how they like it): Shootingparrots.co.uk and psmicrographs.co.uk
  • Human babies are born with no mites, and then their pores slowly become inhabited by them. Every race in all parts of the world has demodex mites – sorry to break the news but none of us are spared!
  • As we age, we become more likely to have a lot of mites in our pores. In fact, 100% of the elderly have demodex mites in their pores. It may be the quality of sebum (oil) not the quantity that makes the pores hospitable for the mites since the elderly outpace teens in skin mite density. There may also be some element of immune underperformance on the part of our skin that allows the mites to thrive.
  • There are two types of mites; they live in different parts of the pores and cause different manifestations of rosacea. Demodex folliculorum lives in the main portion of the pore and it's more likely to cause scaling redness and sensitive skin. Demodex brevis lives deeper in the sebaceous glands (which comes off the pore) and is more likely to cause the papulopustular eruption (rosacea pimples), the symmetrical rashes, and other skin problems arising on the background of a pre-existing rosacea.
  • The B. oleronius bacteria are found on the demodex mites that colonize human skin. It may actually be a protein on the B. oleronius bacterium that is capable of leading to the inflammatory cascade seen in rosacea including ocular rosacea.
  • The bacterium S. epidermidis is a normal skin bacterium, but it is found to be more prevalent in the facial pustules and inflamed eyelash line of rosacea blepharitis.

So what treatments might help with this bacteria-on-the-mite problem? That's an unanswered question since it's a mite versus bacteria versus inflammatory cascade question. At this point, we don't have good care guidelines, so patients and physicians are left to figure this out on their own. Some of the options I discuss with my rosacea patients include:

  • The possibility of trying to treat the mites with oral ivermectin. The mites may come back easily, so repeated treatments over time may be necessary to control demodex.
  • In my practice, I've prescribed permethrin cream nightly for a week. I have my patients repeat this as necessary. However, it is totally an off-label treatment.
  • Several years ago, I attended an American Academy of Dermatology lecture given by a physician practicing in Israel where they use benzoyl peroxide for demodex. Permethrin is not available there  and this physician said she gets good control of facial demodex infestation and rosacea pustules with benzoyl peroxide. Benzoyl peroxide can be irritating to sensitive rosacea-prone skin however.
  • The topical and oral antibiotics that have been the mainstay of rosacea therapy for years still have a role, and it may be that their target is the bacteria on the mite.
  • I find zinc pyrithione in my Calming Zinc ® soap helpful for rosacea. Whether it helps slow down mites, or their bacteria, or is just working on pityrosporum yeast, I don't know, but I always recommend it. I also use the Green Tea Antioxidant Skin Therapy-Replenix Cream to reload the skin's antioxidant reserve, which is depleted by inflammation such as seen in rosacea.  Both of these products are in my Facial Redness Relief Kit. I also recommend that most of my rosacea patients use the Clarisonic Skin Cleansing Brush unless their skin is too sensitive for the brush oscillations. The Clarisonic cleans pores more deeply than other methods of facial cleansing, and the pores are where the mites live. Keep reading below for how I use this information to treat rosacea in my dermatology practice.

The bottom line is that we may be getting closer to understanding rosacea. I expect to see more targeted treatments being developed, and maybe even a cure, as the research continues. For now, the new focus on mites is gross, but fascinating. As a final note the authors of this paper state,

The pathogenic role of Demodex mites, as well as B. oleronius and S. epidermidis, in the induction and persistence of rosacea remains an unresolved issue.

So until then, we patients and physicians have to be creative at trying to reign in the inflammation and skin problems of rosacea. How do I use this information to treat rosacea in my dermatology practice? First and foremost I rely on my Facial Redness Relief Kits to help calm the inflammatory cascade and repair the barrier issues that we know play a role in rosacea. Dermatologist's skin care for rosacea If a person's skin can tolerate the oscillations of a Clarisonic Brush then I recommend the Clarisonic Skin Cleansing Brush System to be used once a day with Calming Zinc Soap or Toleriane Cleanser.  Clarisonic for rosacea I add to these steps a deeply hydrating facial moisturizer matched for skin type. This is important because the skin won't normalize until it's compromised skin barrier issues resolve, and moisturizers help that to happen. I usually recommend my patient applies one of my Daily Moisturizing Face Creams twice a day following the Green Tea Antioxidant Skin Therapy - Replenix. Daily Moisturizing Face Cream Normal to Oily Skin I always tell my patients to wear non-irritating mineral zinc oxide sunscreen since sun exposure also plays a role in unleashing the inflammatory cascade of rosacea. The zinc oxide sunscreens that I use for my patients can be found here. When skin is so exquisitely sensitive that only a non-medicated facial cleanser will work, I recommend Toleriane Cleanser because it won't further the barrier compromise issues with any skin irritation. Toleriane Cleanser ultra gentle cleanser for rosacea My prescription medical treatments include antibiotics that kill the bacterium mentioned above (oral and/or topical), oral or topical miticides to frustrate the demodex (such as permethrin or ivermectin), and IPL (intense pulsed light), which diminishes the blood vessel capillaries and in my experience helps to treat rosacea. I sometimes use topical OTC benzoyl peroxide, such as my Benzoyl Peroxide Acne Treatment Cream, and/or topical mild cortisone creams too. Lastly, I recommend diet modifications to lower the general level of inflammation in the body. Reference: The potential role of Demodex folliculorum mites and bacteria in the induction of rosacea.  Stanisław Jarmuda, Niamh O’Reilly, Ryszard Żaba, Oliwia Jakubowicz, Andrzej Szkaradkiewicz and Kevin Kavanagh Journal of Medical Microbiology Papers in Press. Published August 29, 2012 Photo: Thanks and Gratitude to Horia Varian

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