Demodex Infestation: the Missing Link ?

Written by on October 27, 2011 in Demodex Mites, What Causes Rosacea? with 9 Comments


Firmly in the pure speculation category is a recent paper that proposes that pityriasis folliculorum (or demodex mite infestation) is the missing link in our understanding of rosacea.

Plainly put, Dr. Forton, a dermatologist from Belgium, suggests that rosacea is a two stage disease where 1) demodex mites are allowed to proliferate unchecked and then 2) some mites migrate to the dermis where an immune response leads to the inflammation of rosacea.

The first stage is important because in this theory, the absence of an immune response is able to keep the demodex mites from becoming an infestation.

The author suggests that further research into why there is no immune response during this first stage may lead to further understanding about rosacea.

What We Do Know

  1. We know that a certain bacteria from demodex Bacillus oleronius – can induce an increased immune response in rosacea suffers.
  2. We know that demodex mites are found in normal healthy skin.
  3. Studies have found that in some rosacea sufferers demodex mites are more common.
  4. Arguments still focus on whether demodex mites just enjoy the environment of rosacea skin, or are there making it worse.

My Thoughts

This theory is pretty far fetched I would have thought. We still can’t say what it is about the mites that find them prevalent in some rosacea sufferers, or for sure what link there is between demodex bacteria and an inflammatory response.

Some people do report a decrease in symptoms when they eradicate the mites, but showing that this applies more widely or proving demodex were the actual cause is elusive.

Demodex mites have always been an easy target for those looking for the cause of rosacea. Easy because the mites are easy to find – what has proved harder though is nailing a provable link.

We do need more research. Demodex have been the subject of an enormous amount of rosacea research, so it pains me to say this !

New Abstract

Papulopustular rosacea, skin immunity and Demodex: pityriasis folliculorum as a missing link.

J Eur Acad Dermatol Venereol. 2011 Oct 24., Forton FM, Dermatologist, Private practice, rue Franz Binjé, Brussels, 8-1030 Belgium.

Papulopustular rosacea (PPR) is a common facial skin disease, characterized by erythema, telangiectasia, papules and pustules.

Its physiopathology is still being discussed, but recently several molecular features of its inflammatory process have been identified: an overproduction of Toll-Like receptors 2, of a serine protease, and of abnormal forms of cathelicidin.

The two factors which stimulate the Toll-like receptors to induce cathelicidin expression are skin infection and cutaneous barrier disruption: these two conditions are, at least theoretically, fulfilled by Demodex, which is present in high density in PPR and creates epithelial breaches by eating cells.

So, the major pathogenic mechanisms of Demodex and its role in PPR are reviewed here in the context of these recent discoveries. In this review, the inflammatory process of PPR appears to be a consequence of the proliferation of Demodex, and strongly supports the hypothesis that:

(1) in the first stage a specific (innate or acquired) immune defect against Demodex allows the proliferation of the mite;

(2) in the second stage, probably when some mites penetrate into the dermis, the immune system is suddenly stimulated and gives rise to an exaggerated immune response against the Demodex, resulting in the papules and the pustules of the rosacea.

In this context, it would be very interesting to study the immune molecular features of this first stage, named “pityriasis folliculorum”, where the Demodex proliferate profusely with no, or a low immune reaction from the host: this entity appears to be a missing link in the understanding of rosacea.

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About the Author: David Pascoe started the Rosacea Support Group in October 1998. .

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9 Reader Comments

  1. Brady Barrows says:

    Obviously not all cases of rosacea are demodectic. But the evidence is overwhelming that some cases of rosacea involve demodex mites. While most treatment eradicating the demodex mites improve demodectic rosacea, just as in all cases of rosacea, a few don’t respond to the treatment. The important thing is to rule out demodectic rosacea in the diagnosis which many physicians dismiss because they feel the demodex mite is playing a secondary role in rosacea or is ‘an innocent bystander.” If an increase demodex density count is found, treatment for demodectic rosacea should be done to note any improvement. Dr. Powell suggests this in his book. Eventually ruling out demodectic rosacea will be part of a standard diagnosis process but the long standing pervasive view that demodex mites have a minor role in rosacea has to go by the way side. Demodectic rosacea is firmly established as a variant of rosacea despite this old school mentality that some cling to.

    The article said clearly that a proliferate demodex entity APPEARS to be a missing link in the understanding of rosacea. It is just one link as Dr. Forton points out. There are other links too. He is not saying that it is THE missing link.

    We need more research and for some reason demodex mite research is abundant as you graciously point out. It is so sad that you and I can’t get together and bring the rosacea community together to sponsor our own research funded by rosaceans rather than the current status quo research sponsored by pharmaceutical companies.

  2. Brady Barrows says:

    Here is another article to add the massive list of demodex papers:

    Demodex-associated bacterial proteins induce neutrophil activation.
    O’Reilly N, Bergin D, Reeves EP, McElvaney NG, Kavanagh K.
    Br J Dermatol. 2011 Nov 19. doi: 10.1111/j.1365-2133.2011.10746.x

  3. Brady Barrows says:

    Another article to add to the list was released today:

    Facial dermatosis associated with Demodex: a case-control study.
    Zhao YE, Peng Y, Wang XL, Wu LP, Wang M, Yan HL, Xiao SX.
    J Zhejiang Univ Sci B. 2011 Dec;12(12):1008-15.

    I have added it to the growing list:

  4. The trouble with just listing abstracts related to demodex (and there are a lot) is that most of them just don’t say anything interesting.

    Take the one just mentioned above – it is just a statistical survey. It showed that many patients with “various dermatosis” had demodex mites. This doesn’t help us, we knew that years ago.

    It seems to me what we need is shorter lists of important research – not longer ones.


  5. Brady Barrows says:

    Good idea Dave. How about rosacea sufferers getting together and sponsoring some of their own research? I know that man that can bring them together to do just that. You. Important research.

  6. BYDN says:

    I know nothing of the theory, but after visiting 3 dermatologists over the course of 9 years, with no success on any drug/laser treatment, I came across Dr Forton. Within three months, under her treatment for demodex, my rosacea had cleared.

  7. Hey great to hear that you were able to see Dr. Forton who wrote this article.

    all the best,

  8. Mackbus says:

    BYDN: I’m so happy to hear about your rosacea symptoms. I also went to see Dr. Forton after my own derm here in the States practically laughed me out the door when I mentioned demodex as a possible cause for my roscea. Well, the joke’s on him because with Dr. Forton’s help my skin has made a miraculous turn-around. I have been on meds for about 6 months–I had a very *severe* demodex infestation–and I have been receiving so many compliments on my skin ever since. Visiting Dr. Forton was one of the best things I’ve ever done for myself. She is amazing, and I would recommend her to anyone with rosacea, especially those with papules/pustules. While it’s likely that not all rosacea is linked to demodex, it’s worth testing to see if yours may be. After spending several thousand dollars on laser treatments and antibiotics, 100 euros is all it took to rid myself of a red face.

  9. JAIME says:

    Hello, I’ve suffered with an extreme case of mites for almost a year now, just in the last two months I’ve begun to get under control. They were so bad I lost vision in my left eye and at one point they were literally falling out of my pores of my face. Dr’s that tell you you cant see them are ignorant to a changing mites, 2 species that have evolved and dramatically within just a few years. I am a science researcher and sadly little reasearch has been done to figure out external environmental factors that have led to more and more people suffering from them. Dr’s who choose to believe these mites are either not real or have the ability to attack human skin are the Dr’s making a killing off our pharmaceutical industry, mostly this industry is why nothing more is being done. Millions suffer from these mites and have no where to turn nor know what to do. Anyways…here’s what helped me finally after thousands of dollars trying all different products, over 20 Dr’s telling me i was crazy and countless tears.
    In shower twice a day:
    1)Jason’s brand Tea tree body wash everywhere
    2) tea tree shampoo, wearing gloves rinse out and immediately wrap hair with towel
    3) neutrogena salycic acid face wash
    4) epsom salt whole body scrub into skin wash off
    5) get out of shower pat dry and immediately put cornstarch all over skin
    6) let dry and fall off then spray lice away all over skin
    7) use lice away spray throughout day helps with itching and crawling sensation
    8) spray lysol on everything all day long

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