Rosacea Subtype 6 - Demodicosis

[Brady Barrows]

I want to propose a new Rosacea Subtype 6 - Demodicosis since if you look at the list of rosacea subtypes and variants it is not even mentioned. Mind-boggling isn't it? Yet research grants have been going on for years studying Demodex Folliculorum in Rosacea. Why hasn't anyone done this? Well, I just did. On November 1-2, 2005 there were 363 research papers listed by PubMed in a search with 'demodex.' I went through all of them picking out what I thought relevant to this proposal. There has been research connecting demodex and rosacea going all the way back to 1952. Research connecting rosacea and demodex is still ongoing with the most recent one in Germany completed in August 2005. At the very least Demodicosis should be listed as a variant of rosacea, irrespective of the cause as my editorial on this subject should convince rosaceans that minimizing demodex's role in rosacea is not wise.

For years the medical researchers have been studying demodex folliculorum and rosacea, yet have said that the demodex mite plays only an insignificant role in the etiology of rosacea. Hence, the treatment offered for rosacea rarely took into account the demodex mite. Why this has been neglected is only conjecture. I hope this editorial will at least get the attention of some rosaceans even if the medical community continues to play down the demodex factor in rosacea. Why does demodex folliculorum merit being rated as a sixth subtype or as a variant of rosacea? For the answer, please read my editorial on this subject:

http://www.rosaceans.com/html/demodex.html

[Spav]

Hi Brady,

Just thought i'd add my opinion.

At the moment rosacea subtypes seem to be categorised by the appearance of the rosacea on the skin. The cause of the rosacea is not incorporated to any of the other subtypes. So if subtypes are based on the appearance of the rosacea on the skin then wouldn't Demodex Folliculorum just be another cause for the Papulopustular subtype?

[Brady Barrows]

Hi Brady,

Just thought i'd add my opinion.

At the moment rosacea subtypes seem to be categorised by the appearance of the rosacea on the skin. The cause of the rosacea is not incorporated to any of the other subtypes. So if subtypes are based on the appearance of the rosacea on the skin then wouldn't Demodex Folliculorum just be another cause for the Papulopustular subtype?

I haven't thought of this but you may be right. It is possible that it should be classified a variant rather than a subtype. The main issue is that since Demodex Folliculorum has been the subject of so many reseearch grants that it should be listed somewhere. I suppose that Subtype 5 is according to the condition of the skin too? I would think that it may even be possible to determine whether the number of demodex mites on the face may be a factor, if the bacteria in their guts or on the outside of their bodies is a factor, if the antigen that is released due to their activity is a factor or something else could be differentiated clinically as a test which could then be a 'skin condition' to be classifed as a subtype. No doubt more research is needed. Whatever is the determination of what makes a subtype or a variant of rosacea is, of course, the work of the 'experts,' which I am not one. All I have done is make a proposal, which as a rosacean and a human being is proper. Whether this happens or not is up to the 'experts' and if any 'official' organization listens and responds. Do you think anyone will listen? I can only hope. But rosaceans can make a difference if they want to, or they can sit back and just let the 'experts' and the 'official' organizations keep doing what they are doing. It is quite obvious that most rosaceans prefer the latter, but I am not one of those. At this point all this is simply discussion. Challenges like yours are proper and should be addressed. You have a point. But can you tell me if any of the variants are also classified due to skin conditon or is there some other criteria? No doubt, we can all use an education about subtypes and variants of rosacea.

[Spav]

But rosaceans can make a difference if they want to, or they can sit back and just let the 'experts' and the 'official' organizations keep doing what they are doing. It is quite obvious that most rosaceans prefer the latter, but I am not one of those. At this point all this is simply discussion. Challenges like yours are proper and should be addressed. You have a point. But can you tell me if any of the variants are also classified due to skin conditon or is there some other criteria? No doubt, we can all use an education about subtypes and variants of rosacea.

Brady,

I was just highlighting a potential obstacle. I didn't mean to sound negative.

I must admit i fall into the 'later' category of rosaceans you refer to, i find it hard enough to get through the days, let alone do any of the proactive research you do and for that i give you every credit.

[prryjones]

Brady,
It's my understanding that mites don't CAUSE rosacea. They can only exacerbate the sxs, similiar to the myriad of other environmental insults that also do this...eg sunlight, warmth, spicy foods, cosmetics, etc, etc -- most things in life.
So in this sense, prob. would only make the classification more ambiguous. And not at all accurate.
Perry

[Brady Barrows]

Brady,
It's my understanding that mites don't CAUSE rosacea. They can only exacerbate the sxs, similiar to the myriad of other environmental insults that also do this...eg sunlight, warmth, spicy foods, cosmetics, etc, etc -- most things in life.
So in this sense, prob. would only make the classification more ambiguous. And not at all accurate.
Perry

If you read my editorial I never discuss the subject of whether demdoex mites are the cause. Demodex Folliculorm is the name of a disease or a condition. I am merely proposing that this be a subtype or variant of rosacea. No one knows what the cause is. Whatever criteria is used to determine demodex folliculorm might be used to add this is the list of subtypes or variants of rosacea. My understanding is that whatever is the underlying cause, the demodex factor is an aggravating element and has been the focus of many rosacea research grants for years. One of the variants of rosacea is Steriod-Induced. Steroids don't cause rosacea but surely aggravates the conditon, hence is classified as a variant. Why not Demodex Follicullorum? Untreated rosacea can aggravate until it developes into rhinophyma which is Subtype 3. Untreated rosacea does not cause rosacea yet can develope into a subtype. Why not list Demodex Folliculorum as a subtype too? Irrespective of the cause, there should be some mention of demodex folliculorum since it keeps coming up in clinical studies. Since this keeps coming up I will add a paragraph to my editorial saying I am not proposing this subtype as a cause of rosacea but simply proposing that it either be classified as a subtype or variant.

[prryjones]

Brady,
Demodex folliculorum is the name of a particular species of mite.
I was not aware that steroid induced rosacea is a subtype?
The tone of our reply is defensive. No need to be.
Perry

[Brady Barrows]

Brady,
Demodex folliculorum is the name of a particular species of mite.
I was not aware that steroid induced rosacea is a subtype?
The tone of our reply is defensive. No need to be.
Perry

Perry, Ok. Maybe it should be Rosacea Subtype 6 - Demodicosis instead. I have changed my editorial to reflect this change and propose that it either be listed as either a subtype or at least a variant. This is just a proposal among rosaceans to see if anyone even cares. Steroid Induced rosacea is a variant of rosacea. The NRS lists four:

(1) Granulomatous rosacea
(2) Rosacea Fulminans (pyoderma faciale)
(3) Steroid-induced acneiform eruption
(4) Perioral dermatitis

Another source lists 9 variants of rosacea:

1. Persistent edema of rosacea
2. Rosacea conglobata
3. Rosacea fulminans
4. Ophtalmic Rosacea
5. Lupoid or Granulomatous Rosacea
6. Steroid Rosacea
7. Gram-negative Rosacea
8. Halogen Rosacea
9. Phymas in Rosacea
source >
http://rosacea.dermis.net/content/e02typesof/e02variants/index_eng.html

I did find this interesting tidbit about how they subtype rosacea and why and it goes along with your assertion:

"Definition and subtypes

An expert committee assembled by the National Rosacea Society explicitly defined and classified rosacea in April 2002 into 4 different subtypes based upon specific clinical signs and symptoms. This was an important step in the treatment of rosacea. Currently, the therapeutics of rosacea empirically target the signs and symptoms of the disease because investigators do not understand the details of its pathophysiology. Therefore, this classification system aides clinicians in treatment by highlighting the preponderance of one or more of the clustering signs of presentation and, thus, helps to specify which therapeutic approach to initiate.

The diagnosis of rosacea is a clinical diagnosis. Skin biopsy may be necessary to exclude other disease states that mimic the clinical presentation of rosacea. For example, the clinician must exclude polycythemia vera, connective tissue diseases (eg, lupus erythematous, dermatomyositis, mixed connective tissue disease), photosensitivity, carcinoid mastocytosis, long-term application of topical steroids, contact dermatitis, and photosensitivity before making the diagnosis of rosacea. Rosacea is defined by persistent erythema of the central portion of the face lasting for at least 3 months. Supporting criteria include flushing, papules, pustules, and telangiectasias on the convex surfaces. Secondary characteristics are burning and stinging, edema, plaques, a dry appearance, ocular manifestations, and phymatous changes. The prevalence of these findings designates the subclassification of the presentation and, additionally, the therapeutic options."
source >
http://www.emedicine.com/derm/topic377.htm

This same article says further down the page,

"Microbial organisms

Demodex species (mites that normally inhabit human hair follicles) may play a role in the pathogenesis of rosacea. Support suggests that Demodex prefers skin regions that are affected in rosacea, such as the nose and cheeks. Studies also support that an immune response of helper-inducer T cell infiltrates occurs, surrounding the Demodex antigens in patients with rosacea. Yet, conflicting evidence indicates that Demodex does not induce an inflammatory response in patients with rosacea. Moreover, Demodex is found in large numbers of healthy individuals without rosacea. More studies need to be performed to determine whether Demodex truly is pathogenic."

Statements like the above keep appearing in rosacea articles and papers and I am only proposing that either a variant or subtype be listed along with the others that includes demodex. The secondary characteristics should also include findings on demodex so that, as it says above, "the prevalence of these findings [including demodex findings] designates the subclassification of the presentation and, additionally, the therapeutic options." Why they leave this out is curious to me.

[prryjones]

Nothing against your proposal. I just think that so many classifciation schemes (which differ according to who is doing the classifying) serve only to confuse and complicate.
An expample is the "gram neg folliculitis" type rosacea listed on your link. I am familiar with both folliculitis (bacterial infection) and the term "gram neg" (staining procedure used to classify bacteria into either one or two groups -- I've done a ton of these). And I thought bacteria were ruled out a causative agent of rosacea? It reaches a point where anything that causes a red face - even transiently - can be classified as a rosacea subtype. To me this is ridiculous. And the reason this irritates me is because as long as folks keep focusing on those things that can only exacerbate rosacea - eg mites, sun, "gram neg folliculitis", etc - then in my opinion the focus is not where it should be, that of finding the real underlying cause of rosacea, either on the molecular level (signalling systems, etc.) or if probed deeper, the genetic cause.
And to me this is frustrating.
Anyway, you get the last word on this exchange or ours. I just think that as long as these exacerbating factors are focused on, the ultimate eitiology will remain a mystery.
I doubt whether anyone besides us has been either entertained or educated by this discussion, so how about PMing me if you want to talk about it further?
Perry

[Brady Barrows]

Perry,
Look what I found:

A clinico-pathological approach to the classification of human demodicosis.

Akilov OE, Butov YS, Mumcuoglu KY.

Department of Dermatology, Cosmetology Hospital "Aesthetics", Ekaterinburg, Russian Federation.

BACKGROUND: Demodicosis is a parasitic skin disease caused by the follicle mites Demodex folliculorum and Demodex brevis. Although there are several clinical variants of this disease, a clear classification is missing. OBJECTIVE: To characterize the clinical features and course of the different forms of demodicosis. PATIENTS: Prospective study of 87 patients with clinical symptoms of demodicosis and positive acarological findings. Each patient was examined an average of six times during the treatment period. RESULTS: We suggest that demodicosis be divided into both primary and secondary types. The usual etiological agent of primary demodicosis is D. folliculorum, which causes an erythemato-squamous eruption in the facial T-zone. The rash starts on unaltered skin and covers 8 - 15 % of the face. Pruritus accompanies the onset of the rash, while erythema is first apparent after papulo-pustules are seen and disappears after treatment. Half the patients show seasonal exacerbations. Secondary demodicosis is usually caused by D. brevis and characterized by a symmetrical malar papulo-pustular eruption. It develops on diseased skin and covers 30 - 40 % of the face. Pruritus starts after the lesion exacerbation, but erythema precedes the papulo-pustular phase and persists after treatment. Most patients flare during the summer. The facial distribution, seasonality and pathogenesis, as well as the species of mite involved, must be taken into consideration in separating the various forms of demodicosis.
source >
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=16033479&query_hl=4

And one more report:

Demodicidosis revisited.

Baima B, Sticherling M.

Department of Dermatology, University of Leipzig, Germany. baib@vz.uni-leipzig.de

Demodex mites are common commensals of the pilosebaceous unit in mammals. In humans, only two species (Demodex folliculorum and D. brevis) have been identified and have been implied to play a role in at least three facial conditions: pityriasis folliculorum, rosacea-like demodicidosis and so-called "demodicidosis gravis". However, there is no consensus to what degree the mites are causative of the skin pathology and how they might contribute to the disease. This review presents a demodicidosis case, discusses the clinical features of Demodex infestation in man and reviews its pathogenetic implications and the therapeutic options.
source>
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12013194&query_hl=4

Another report:

"A leading theory suggests a vascular basis; however, clinical observations and histopathologic studies suggest that inflammation of the pilosebaceous follicle may be central to the pathogenesis of rosacea. Demodex folliculorum is a frequently seen commensal in the follicles of facial skin. According to evidence from biopsies of the skin surface, individuals with rosacea have a higher density of this parasite. This increased mite density may play a role in the pathophysiology of rosacea by triggering inflammatory or specific immune reactions, mechanically blocking the follicles, or acting as a vector for bacteria. Ongoing research has shown that bacteria from patients with rosacea may behave differently at the higher skin temperature that may be present in patients with rosacea. Another group has isolated bacteria from the Demodex mites; these bacteria may play a pathogenic role in papulopustular rosacea by facilitating follicular-based inflammatory changes." source >
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15499752&query_hl=1

Research reports like the following continue to list demodex as one of the possible causes of rosacea >

"The cause of rosacea remains somewhat of a mystery. Several hypotheses have been documented in the literature and include potential roles for vascular abnormalities, dermal matrix degeneration, environmental factors, and microorganisms such as Demodex folliculorum and Helicobacter pylori." source >

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15337973&query_hl=1

If democodosis is a different disease, then why do research papers continue to list demodex folliculorum mentioning rosacea? It is because democodosis looks so much like rosacea. That is why democodosis should be listed either as a subtype or a variant of rosacea. This only makes sense if the presence of demodex folliculorum is identified by clinical methods used to determine democodosis.

And here is an interesting report:

Is demodex really non-pathogenic?

Pena GP, Andrade Filho JS.

Laboratorio Distrital Centro-Sul, Prefeitura de Belo Horizonte, Minas Gerais, Brasil. gilpena@gold.com.br

Although usually considered a non-pathogenic parasite in parasitological textbooks, Demodex folliculorum has been implicated as a causative agent for some dermatological conditions, such as rosacea-like eruptions and some types of blepharitis. Several anecdotal reports have demonstrated unequivocal tissue damage directly related to the presence of the parasite. However, this seems to be exceedingly rare, in contrast with the marked prevalence of this infestation. We have had the opportunity to observe one of such cases. A 38-year-old woman presented with rosacea-like papular lesions in her right cheek. Histopathological examination revealed granulomatous dermal inflammation with a well-preserved mite phagocytized by a multinucleated giant cell. This finding may be taken as an evidence for the pathogenicity of the parasite, inasmuch as it does not explain how such a common parasite is able to produce such a rare disease.
source >
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=10887379&query_hl=1