Rosacea Demodicosis

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Please Note: Because a couple of the MAC members are having problems accessing the forum due to our tight security, I asked the following question to all the MAC members by email and the responses are posted below. We are working on how to make the forum a bit more user friendly or understandable to not only the MAC members but for everyone. I have asked a number of volunteers to help with this project and will announce the results in the future. A few of the MAC members haven't joined the forum, so hopefully they will reply to the question below, which I have always wondered about. Here is the intial question to the MAC:

Question for the RRDi Medical Advisory Committee:

Could you comment on why rosacea demodicosis has never been considered a variant or subtype of rosacea, yet continues to be researched and mentioned in many clinical studies and papers?

Could rosacea demodicosis be considered a variant of rosacea or could it be considered a subtype along with the four other subtypes (ETR, Papulopustular, Phymatous, Ocular)?

Brady Barrows

The responses:

From: Dr. Brodell

Subject: Re: Question for the RRDi Medical Advisory Committee

Date: January 25, 2007 2:23:42 AM HST

To: BB

The main subtypes of rosacea have been named because of their clinical features, not the underlying mechanism which produces them. This is because these mechanisms remain controversial. With regard to demodex, it is clear that demodex mites are found in increasing numbers in patients with rosacea, BUT are these present because rosacea produces fertile ground for their growth or are they the root cause of the rosacea. This has not been clearly determined.

Dr. Bob Brodell

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From: BB

Subject: Re: Question for the RRDi Medical Advisory Committee

Date: January 25, 2007 6:18:03 PM HST

To: Dr. Brodell

Dr. Brodell,

Please bear with me since I obviously don't understand this subject since I am asking the question.

My understanding is that these are the subtypes of rosacea:

ETR, Papulopustular, Phymatous, Ocular, Neuropathic Rosacea, and Glandular Rosacea.

I am not discussing the the underlying mechanism being demodex. If the subtypes are classified due to their clinical features, my understanding is that a simple microscopic test can reveal if the number of demodex mites are above average in a rosacea patient. That would present a clinical feature that can be observed and wondered why it isn't considered a subtype?

I don't understand how they classify a variant of rosacea. My understanding is that the variants of rosacea are:

Granulomatous Rosacea, Rosacea Fulminans, Steroid-Induced Rosacea, Perioral Dermatitis, Persistent edema of rosacea, Gram-Negative Rosacea, Halogen Rosacea, Rosacea Conglobata, and Rosacea Inversa.

What is the difference between classifying rosacea as a subtype or variant? If is the clinical features with subtypes, what is the criteria for classifying rosacea as a variant?

And my original question still is why isn't Rosacea Demodicosis not even mentioned when the clinical studies are revealing that demodex plays a factor in rosacea. I can list for you a long list of clinical studies.

Brady Barrows

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From: Dr. Brodell

Subject: Re: Question for the RRDi Medical Advisory Committee

Date: January 26, 2007 1:13:58 AM HST

To: BB

The key issue is whether demodex inhabit abnormal skin that is already "rosacea"....like putting a wet piece of bread on a table and coming back 3 days later to see a variety of molds growing on the bread...or whether demodex is a primary pathophysiologic factor in causing rosacea. In fact, if the latter is true,and if the cause of a particular case of rosacea is either proprionobacterium acnes, demodex, pityrosporon, etc....then the entire schema of rosacea types needs to be revamped so we can make a diagnosis that would be linked to the most appropriate treatment. Wouldn't it be great if we knew that rosacea with many pustules is the type associated with demodex....and this type responds most effectively to topical permethrin! Then, I would call this type the pustular-demodex variant and voila...progress. The problem is that we just do not have the science to back up this type of schema.

Dr. BOB

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From: Dr. Jones

Subject: RE: Question for the RRDi Medical Advisory Committee

Date: January 25, 2007 6:02:51 AM HST

To: BB

My understanding is that the four current subtypes are based on purely clinical features. Demodex-associated rosacea probably can’t be diagnosed on clinical features alone and at this point would require identification of the mite through some sort of lab test.

-Dave

From: BB

Subject: Re: Question for the RRDi Medical Advisory Committee

Date: January 25, 2007 6:20:33 PM HST

To: Dr. Jones

Dr. Jones,

Please bear with me since I obviously don't understand this subject since I am asking the question.

My understanding is that these are the subtypes of rosacea:

ETR, Papulopustular, Phymatous, Ocular, Neuropathic Rosacea, and Glandular Rosacea.

I am not discussing the the underlying mechanism being demodex. If the subtypes are classified due to their clinical features, my understanding is that a simple microscopic test can reveal if the number of demodex mites are above average in a rosacea patient. That would present a clinical feature that can be observed and wondered why it isn't considered a subtype?

I don't understand how they classify a variant of rosacea. My understanding is that the variants of rosacea are:

Granulomatous Rosacea, Rosacea Fulminans, Steroid-Induced Rosacea, Perioral Dermatitis, Persistent edema of rosacea, Gram-Negative Rosacea, Halogen Rosacea, Rosacea Conglobata, and Rosacea Inversa.

What is the difference between classifying rosacea as a subtype or variant? If is the clinical features with subtypes, what is the criteria for classifying rosacea as a variant?

And my original question still is why isn't Rosacea Demodicosis not even mentioned when the clinical studies are revealing that demodex plays a factor in rosacea. I can list for you a long list of clinical studies.

And why can't 'a diagnosis be determined on clinical features alone' when a simple microscopic test reveals the mite density?

Brady Barrows

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From: Dr. Jones

Subject: RE: Question for the RRDi Medical Advisory Committee

Date: January 26, 2007 8:58:19 AM HST

To: BB

Seems largely arbitrary to me too, but there´s no doubt that it has use in talking about the disease. Classification issues frustrate everyone, and the reason it´s so difficult in rosacea is that the pathogenesis is so poorly understood. As I see it, subtypes usually refer to things that would be generally recognized as central components of the main disease spectrum, whereas variants refer to types that are less common and have some particular feature that makes them stand out noticeably from the main spectrum of disease. In rosacea, classification is based on clinical criteria, because that´s about all we have to go on. I suppose you´re right that there´s no reason to exclude demodex counts as a clinical criterion and then if there´s an uncommon subgroup of patients with really high counts as a defining feature you could call it a variant. It´ll be tough to get clinicians to spend time doing the test, though.

I think the biggest question is still how does demodex contribute to the pathophysiology, and can that understanding help us treat the disease.

David A. Jones, MD, PhD

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From: Dr. E.J.van_Zuuren

Subject: RE: Question for the RRDi Medical Advisory Committee

Date: January 25, 2007 6:48:11 AM HST

To: BB

Hi Brady,

I keep on having difficulties to surf through the RRDi site,

I cannot find this MAC question

However I will answer it now. I am not an rosacea expert, I don't see rosacea patients, only allergy patients. I only performed the systematic review on treatments for rosacea. The questions on the several subtypes should be answered by the real rosacea experts. I think you can make many more subtypes or variants, but the idea of the classification was to categorize the subtypes for those who do research. The more subtypes you make to more difficult it will become I think

Best wishes Esther

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From: Dr. Latkany

Subject: Re: Question for the RRDi Medical Advisory Committee

Date: January 25, 2007 1:48:21 PM HST

To: BB

Sorry but I have no comment on this. I just lump all of them into one category because from an eye standpoint they all act the same and are treated the same way.

RL

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From: Dr. Draelos

Subject: Re: Question for the RRDi Medical Advisory Committee

Date: January 25, 2007 2:15:36 PM HST

To: BB

Dear Brady,

Thank you for your question. Not everyone agrees that Demodex is operative in the pathogenesis of rosacea. Rosacea is probably a collection of many different diseases that are lumped together inappropriately.

Best Wishes,

Zoe Diana Draelos, MD

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From: BB

Subject: Re: Question for the RRDi Medical Advisory Committee

Date: January 25, 2007 6:23:02 PM HST

To: Dr. Draelos

Dr. Draelos,

I can really appreciate your comment that rosacea is 'probably a collection of many different diseases lumped together inappropriately.'

Please bear with me since I obviously don't understand this subject since I am asking the question.

My understanding is that these are the subtypes of rosacea:

ETR, Papulopustular, Phymatous, Ocular, Neuropathic Rosacea, and Glandular Rosacea.

I am not discussing the the underlying mechanism being demodex. If the subtypes are classified due to their clinical features, my understanding is that a simple microscopic test can reveal if the number of demodex mites are above average in a rosacea patient. That would present a clinical feature that can be observed and wondered why it isn't considered a subtype?

I don't understand how they classify a variant of rosacea. My understanding is that the variants of rosacea are:

Granulomatous Rosacea, Rosacea Fulminans, Steroid-Induced Rosacea, Perioral Dermatitis, Persistent edema of rosacea, Gram-Negative Rosacea, Halogen Rosacea, Rosacea Conglobata, and Rosacea Inversa.

What is the difference between classifying rosacea as a subtype or variant? If is the clinical features with subtypes, what is the criteria for classifying rosacea as a variant?

And my original question still is why isn't Rosacea Demodicosis not even mentioned when the clinical studies are revealing that demodex plays a factor in rosacea. I can list for you a long list of clinical studies.

I am not discussing the pathogenesis of rosacea being demodex. I understand that the cause of rosacea is unknown.

Brady Barrows

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From: Dr. Draelos

Subject: Re: Question for the RRDi Medical Advisory Committee

Date: January 26, 2007 3:06:08 AM HST

To: BB

Dear Brady,

Rosacea was classified by a panel who reached a consensus on the groups you mentioned. These are groups based on appearance of the face. They are considered stages of rosacea as untreated rosacea will progress from one group to another in the order that you listed. Demodex are not visible to the human eye. Thus, this factor was not selected for the grouping.

Best Wishes,

Zoe Diana Draelos, MD

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From: BB

Subject: Re: Question for the RRDi Medical Advisory Committee

Date: January 26, 2007 7:26:37 AM HST

To: Dr. Draelos

Dr. Draelos,

Now that explains it. You are the only doctor who has explained this to me. It is odd to me that the variants can be differentiated by the eye.

Since more and more clinical studies are finding demodex mites in a significant number of rosacea patients, rosacea demodicosis should be considered either a subtype or variant some day in the future. I thought it would be something that the RRDi could be a part of.

I have read how many research papers you have written and how many committees your serve on. If you could use your influence to obtain a grant that the RRDi could sponsor, our three volunteer professional grant writers could write it up, the MAC could approve it, and the RRDi could then have a research paper published. We have sent letters to the pharmaceutical companies for either a donation or grant and can't get passed a massive wall of no response.

I know I have probably used up your 15 minutes of volunteer time this month already, but keep us in mind if you are in the right place and the right time and remember irosacea.org to someone who has the purse strings to fund a study.

Brady Barrows

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From: Dr. Joel T. Bamford

Date: January 29, 2007

To: Brady Barrows

 

Demodex is part of the normal flora of facial hair follicles. Thus far, there is not proof (scientific) that it causes or makes rosacea worse.

A very nice study at the NRS research forum two (?) years ago, explained how tetracyclne could supress the bacteria whiich live in demodex, suggesting how TCN 'might' work if it worked by affecting demodex. The study did not show it was the cause of rosacea!

But tcn also works to block a variety of factors in inflammation process.

Dr. Bamford

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From: Gerg Plewig, M.D.

Subject: Demodicosis

Date: February 14, 2007 7:55:58 AM HST

To: BB

Dear Brady

Demodicosis is a disease sui generis. Demodicosis in animals (mange) is sometimes a serious disease.

Demodex-folliculorum-mites infest the infundibula of sebaceous follicles, rarely those of vellus hair follicles. They are either innocent bystanders or cause folliculitis or abscesses.

Rosacea patients usually have a high degree of demodex-folliculorum-mites in their facial follicles, thus aggravating a pre-existing rosacea (analogous to steroid rosacea).

Or a demodicosis can clinically mimick rosacea sui generis.

Best regards

Gerd Plewig
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Question for the MAC:

I have read all the replies and want to understand something. Dr. Plewig above says that demodicosis is a disease 'sui generis' which according to my understanding is a skin disease altogether different from rosacea, but Dr. Plewig adds is "analogous to steroid rosacea." My question is this. The NRS classifies STEROID INDUCED acneiform eruption as a rosacea variant. Wouldn't it be logical to say that since Steroid Induced rosacea is a variant and demodicosis is analogous to steroid rosacea that demodicosis could also be listed as a variant? Here is the list of variants of rosacea that I have found in research papers:

1. Granulomatous Rosacea

2. Rosacea Fulminans

3. Steroid-induced acneiform eruption

4. Perioral dermatitis

5. Persistent edema of rosacea

6. Gram-negative Rosacea

7. Halogen Rosacea

8. Rosacea Conglobata

9. Rosacea Inversa

10. Lymphedema (Morbihan's disease)

11. Gnatophyma

12. Metophyma

13. Motophyma

14. Blepharophyma

Since Steroid Induced rosacea aggravates rosacea, wouldn't demodicosis be in the same group as the above variants of rosacea? Why exclude it? Since Dr. Draelos says above that rosacea is 'probably a collection of many different diseases lumped together inappropriately,' it seems that classifying rosacea into variants would at least help physicians to rule out demodicosis when examaning patients and diagnosing the skin condition.

Another question is about variants. Since subtypes are diagnosed by the eye and a history of the patient, (according to Dr. Draelos) how does a physician diagnose a rosacea variant? Is this done simply by the eye and a history too?

Brady Barrows

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From: Gerd Plewig, M.D.

Subject: AW: question

Date: March 2, 2007 5:05:02 AM HST

To: BB

Dear Brady,

Concerning your questiones, demodicosis can be a disease by itself and thus being independent of rosacea. Or demodex mites heavily colonize pre-existing rosacea and thus lead to demodectic rosacea ( rosaceiform dermatosis). This is a rather complicated issue. Rosacea is usually diagnosed by inspection the eye. Laboratory tests are rarely needed, for instance in gram-negative rosacea, where one needs bacteriology.

The same is true for demodectic rosacea, where one has to demonstrate the mites in great numbers.

Best regards,

Gerd Plewig, M.D.
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So far, this is all the replies, and if I get anymore I will post them here for your viewing.

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