Monday, November 24, 2025

Case of the Week 794

This week's case is from Dr. Steven Ruhoy and Tracie Rose. The patient is an elderly woman with a very itchy rash which is worse at night. The family practitioner noted excoriations on the plantar aspect, but did not see any definitive burrows. She performed a skin scraping which revealed the following on H&E-stained histologic section. What is your identification?


7 comments:

Anonymous said...

Pediculus humanis

Anonymous said...

The general morphology fits that of an insect or arthropod with a head, thorax and segmented abdomen. On the top of the head there is a series of round or circular organs suggesting complex eyes typical of insects, the thorax bears legs. The abdomen has segmentations, an oval large object suggests the presence of an egg. Following the lead of the previous comment, I would agree on the identification of a body louse and the symptoms also indicate Pediculus humanus. The more common head louse seldom ventures that far from its own niche.
Florida Fan

Anonymous said...

Doesn't look like a parasite but I never analyze histological samples./Patrik

Anonymous said...

Incredible. Today is our practical is on ectoparasites. November 11th was our Cestodes practical. Very helpfully, we can refer our students to your blog as we teach each parasite! Are you doing it on purpose? Are we? Kind regards from Entomology & Parasitology teaching at LSHTM.

Anonymous said...

Scabies

Anonymous said...

Some sort of ectoparasite, my first thought was a louse.

Anonymous said...

tungiasis