The best way of counting demodex mites

[David Pascoe]

Just published is the following paper.

Comparison of the two techniques for measurement of the density of Demodex folliculorum: standardized skin surface biopsy and direct microscopic examination.

Department of Dermatology, Başkent University Faculty of Medicine, 5. Sokak no. 48, Bahçelievler 06490, Ankara, Turkey.

Background:

In daily dermatological practice, many dermatologists do not include demodicosis in their differential diagnoses, or the diagnosis of demodicosis is frequently masked by other skin diseases such as papulopustular or erythematotelangiectatic rosacea, seborrhoeic dermatitis, perioral dermatitis and contact dermatitis. There are two methods for measurement of the density of Demodex folliculorum (Dd): standardized skin surface biopsy (SSSB) and direct microscopic examination of fresh secretions from sebaceous glands (DME). No study has been reported in the literature comparing the diagnostic value of these two techniques.

Objectives:

To compare the value of the two techniques, SSSB and DME, for the measurement of Dd in patients with suspected demodicosis. Methods Mite density was investigated using SSSB and DME in 37 patients with facial skin lesions suggesting demodicosis. Two samples, one for SSSB and one for DME, were obtained from a cheek lesion of each patient.

Results:

Twenty-three (62%) patients were diagnosed with demodicosis according to their clinical manifestations combined with a high Dd (Dd > 5 mites cm(-2)) with SSSB and/or DME. In all the patients, the mean Dd measured with SSSB was higher than that with DME (22.9 +/- 5.9 and 2.2 +/- 0.8, respectively; P = 0.001). Also, among the 23 patients with demodicosis, the mean Dd measured using SSSB was higher than the mean Dd with DME (36.5 +/- 8.3 and 3.4 +/- 1.2, respectively; P = 0.0001).

Conclusions:

We recommend the use of SSSB for the measurement of Dd as more patients with demodicosis can be diagnosed with this method compared with the DME method.

Basically the paper is saying that the standardized skin surface biopsy is the most reliable way to count demodex mites and recommends this as the best way to get a diagnosis of demodicosis.

[Aurelia]

Thanks, David.

"In daily dermatological practice, many dermatologists do not include demodicosis in their differential diagnoses, or the diagnosis of demodicosis is frequently masked by other skin diseases such as papulopustular or erythematotelangiectatic rosacea, seborrhoeic dermatitis, perioral dermatitis and contact dermatitis."

We have been hearing for years that many cases diagnosed as rosacea are instead demodicosis, and especially in China. Surely the diagnosis can't be made just by the numbers of mites involved?

I wonder if Colin Dahl has returned to Australia yet after spending the winter in China? You will remember him telling us in June 2008: "At the moment I am in China, establishing a Rosacea clinic.
You would be surprised the large percentage of people in Western China who suffer from Rosacea." It would be interesting to hear from him again.

Kind regards,

Aurelia

[starbuck]

Are lesions and scales a prerequisite for demodex infestation? Or should anyone with reddish skin, flushing and some red bumps should get tested for demodex?

[David Pascoe]

My understanding of the accepted norms is that yes, you would need to have something like scales or flakes or pustules before suspecting the infestation of demodex.

Some treatments that work for the papules and pustules of rosacea also interfere with bacteria from demodex so one may find the demodex effect drops at the same time as the rosacea inflamation decreases with say for eg. oral antibiotics.

If this does occur, then it makes it hard to prove that demodex is an issue for you. We get to the chicken and egg argument. This argument with demodex is still ongoing in the mind of researchers - do they cause rosacea or just like living in rosacea skin ?

davidp.

[annerainbow]

I have scraped myself, found mites - both species - follicularum and brevis, treated the mites with great improvement but i didnt have any flaking or scaling on my face - redness, papules and pustules with "lumpy" skin when you pressed firmly - partic around the chin area. I am inclined to think that it is not the numbers of mites that cause symptoms, but our bodies individual reaction to them (or something they harbour - like a bacteria) that is the problem. The solution as i see it is to kill the mites - and that seems to be the difficult thing in humans.

I'm a vet and have treated many canine demodecosis cases with oral ivermectin, but at much much higher daily doses than are prescribed for humans.

I will post a question asking about the different treatment protocols that have been prescribed for ivermectin and their efficacy.

Anne Rainbow