Dermatology: Practical and Conceptual


Image Letter  |  Dermatol Pract Concept 2021;11(2):e2021015 1

Dermatology Practical & Conceptual

Is It Possible to Improve Scabies 
Diagnosis Performance?

Vincenzo Greco1, Massimiliano Scalvenzi1, Gabriella Fabbrocini1, Matteo Megna1

1 Dermatology Unit, Department of Clinical Medicine and Surgery, University of Naples Federico II, Italy

Key words: scabies, mite, feces, eggs, jetliner, jet trail, polarized light, dermoscopy

Citation: Greco V, Scalvenzi M, Fabbrocini G, Megna M. Is it possible to improve scabies diagnosis performance? Dermatol Pract Concept. 
2021;11(2):e2021015. DOI: https://doi.org/10.5826/dpc.1102a15

Accepted: August 31, 2020; Published: April 12, 2021

Copyright: ©2021 Greco et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License BY-
NC-4.0, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original author and 
source are credited.

Funding: None.

Competing interests: The authors have no conflicts of interest to disclose.

Authorship: All authors have contributed significantly to this publication.

Corresponding author: Vincenzo Greco, MD, Department of Dermatology, University of Naples Federico II, Via Pansini 5, 80131 Naples, 
Italy. Email: vingreco@live.com

Case Presentation 

We present the same case of scabies (Figure 1A) photographed 

with a new polarized light dermoscope (Figure 1B) and with 

an older immersion contact dermoscope (Figure 1C).

Teaching Point

Dermoscopy allows a high sensitivity and specificity for 

scabies diagnosis [1]. Although modern dermoscopes  

with polarized light can better analyze pigmented lesions 

Figure 1. (A) Scabies: clinical aspects. (B) Polarized light dermoscopy. (C) Immersion contact dermoscopy.



2 Image Letter  |  Dermatol Pract Concept 2021;11(2):e2021015

without necessitating a liquid interface or direct skin 

contact with the instrument, they do not perform as well 

when interpreting superficial epidermal lesions of scabies. 

Note that, with new polarized light dermoscopes, the “jet 

trail” (the burrow) is easily visible, but a clear differen-

tiation of artefacts induced by scratching or small dirt 

particles is not easy to obtain [2]. Paradoxically, scabies 

was more easily detected in the past with older dermo-

scopes because immersion contact dermoscopy reduces the 

reflection capacity of keratinocytes of the burrow so that 

the “jetliner,” feces, and eggs that are usually covered by 

the shiny keratinocytes of the jet trail, are better detected. 

In conclusion, we suggest using older dermoscopes or the 

immersion technique for mite search.

References

1. Marghoob AA, Swindle LD, Moricz CZ, et al. Instruments and 

new technologies for the in vivo diagnosis of melanoma. J Am 

Acad Dermatol. 2003;49(5):777–799. DOI: 10.1016/s0190-

9622(03)02470-8. PMID: 14576657

2. Micali G, Lacarrubba F, Verzì AE, Chosidow O, Schwartz RA. 

Scabies: advances in noninvasive diagnosis. PLoS Negl Trop Dis. 

2016;10(6):e0004691. DOI: 10.1371/journal.pntd.0004691. 

PMID: 27311065.