This week's case is from Sandeep T, the same individual who contributed the amazing Case 409 from many years past. The current case is less dramatic, but a beautiful example of a classic. The following were seen on skin scrapings from a young man with a 2-month history of severe itching in the back of his left ear. The physician suspected fungal infection and ordered a KOH wet mount of the skin scrapings. This is what was seen. Identification?
11 comments:
Oh yes, this mite has been found mostly serendipitously while reading the direct smear looking for fungi. Good thing the Calcofluor KOH stain will make the mite fluoresce under UV light excitation. That’s how I found Demodex folliculorum most of the time.
Florida Fan
Scabies
# we did a AFB stain and mite colored Red! I have seen extensively in the scraping area studies, it was feeding on fungal hyphae (T mentagrophytes grown on culture). It is a know fact that Demodix feed on bacteria (lepra)..please have a read on our communication concomitant TF with PF(demodicosis) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6150771/
Possibly Demodex species?
I agree with the above people. We just covered Demodex in veterinary school, and my professor noted that a major way to identify them is based on their long, slender "cigar shape." I am not sure how one would go about getting a species level identification, but I would assume it would be folliculorum, as Florida Fan said. The other options would be brevis, but I think our friend here is too slender and chic.
-Josh
Yes! This would be Demodex!
Funny to know that above a certain age threshold, prevalence reaches almost 100%!
You’ll never feel lonely anymore - “me and my Demodex buddies, right”!
These are most often harmless, but can be the cause of rosacea and sometimes even worse if I remember well...
Perhaps Idzi that is why it is the peoples mite. "Demo" Greek for people
Actually Demo dex is Greek for "Fat" "Woodworm"
Demodectic mite.
Not sure about humans but normal flora on dogs and usually cause problems only in juvenile and immunosuppressed patients. The clinical significance wools depend on the species of mite, the number of mites (ie. Proliferation above normal flora frequency) and the correlation with clinical signs
According to the descriptions of Desch & Nutting, 1972 the present mite should belong to D. folliculorum. I think all of us agree that the itching on the ear of the patient does nothing to do with the presence of the mite. In my courses, I ask my students to take some material from their ears and always in 2 or 3 of them we find this mite. As D. brevis inhabits rather the sebaceous glands, it is difficult to find it in regular skin scrapings, but rather in histologic preparations.
Desch C, Nutting WB. Demodex folliculorum (Simon) and D. brevis Akbulatova of man: redescription and reevaluation. J Parasitol. 1972;58(1):169-177.
Hi Kosta, how do you have your students collect their ear samples? Outer ear canal, pinnae, helix? I just tried my own but no luck. I've tried skin scrapings and eyebrows before with no luck. I'd welcome suggestions from the group; I think this would be such a fun teaching tool!
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