Presenter : Dr Anil Kumar B CModerator: Dr Asha G S

SCYBALA

Scyb´a`la -- Hardened masses of feces(Webster Dictionary)

Purpose of this presentation

Scybala as a diagnostic finding- scabies

Diagnostic Challenges in Scabies.

Introduction

BackgroundScabies is an intensely pruritic, highly

contagious infestation of the skin Arachnid mite Sarcoptes scabiei, variety

hominis. Originally, scabies was a term used by the

Romans to denote any pruritic skin disease.

In the 17th century, Giovanni Cosimo Bonomo identified the mite as one cause of scabies.

BackgroundLike syphilis, scabies has come to be

known as the great imitator

Its spectrum of clinical manifestations may lead the practitioner to the wrong diagnosis

The phrase "7 year itch" was first used with reference to persistent, undiagnosed infestation with scabies

Scabies is an intensely itchy dermatosis caused by the mite Sarcoptes scabiei

Patient with ordinary scabies may have an average of 12 mites

Crusted scabies may have millions of mites

The usual methods of scabies diagnosis includemicroscopic identification of the mites eggs feces in skin scrapings

In many cases the results of microscopic examination can be negative owing to the low number of parasites present in the cornfield layer

Guideline for the diagnosis and treatment of scabies in Japan Norihisa Ishii

The guideline has been prepared by the Japanese Dermatological Association to ensure proper diagnosis and treatment of scabies

For making a proper diagnosis, the following three points should be taken into considerationClinical symptomsDetection of the mite (Sarcoptes scabiei) and its

parts Epidemiological symptoms

The Japanese Dermatological Association, Tokyo, Japan 07/2008

Diagnosis is based on clinical findings and the demonstration of the mite

Microscopic examination of the skin scrapings from the patient is essential to demonstrate the mites

The specimen from the crusted lesion is scraped with a blunt scalpel and placed on a glass slide

A drop of mineral oil and a cover slip are placed on it

The microscopic examination reveals Numerous mitesEggs Mite feces (scybala)

Diagnosis

The presence of scabies parts evident as solid pink eosinophilic fragments is diagnostic, representing the chitinous exoskeleton of the Sarcoptes scabiei mite

Histopathology finding

Pink pigtails can also be seen occasionally within the stratum corneum and are thought to represent remnants of the egg shell

Demonstration of mites, eggs and mite feces (scybala) is diagnostic of scabies

Epiluminescence microscopy and high-resolution video-dermatoscopy are noninvasive techniques that allow Detailed inspection of the skin From the surface to the superficial papillary

dermisCan be used to visualize the mite

"Mini Triangle Sign "

Dermoscopic features “mini-triangle signs” in maturing scabies’ eggs

Classic dermoscopic image of triangle or “delta wing jet” sign of dense scabies head parts (long red arrow), relatively translucent scabies body (long black arrow), scabies eggs (short red arrows), and classic S shaped burrow.

Microphotograph of mineral oil scabies preparation showing mite (below heavy black arrows), eggs (orange arrows), and scybala (yellow arrows).

In preparing an ex vivo scabies preparation, mineral oil preserves scabies’ scybala whereas potassium hydroxide does not

The technique for obtaining a scabies preparation is that of a very superficial shave biopsy (without anaesthesia), with the scalpel blade virtually parallel to the skin.

Microphotograph of scabies scybala (yellow arrows) as the only diagnostic microscopic finding confirming presence of scabies.

Scybala may be the only diagnostic finding, mineral oil is the preferred agent for preparing slidesPotassium hydroxide and mineral oil

preparations will demonstrate eggs and mitesDermoscopy employs magnification and light

in such a way as to render the skin surface translucent, allowing visualisation of patterns that are often not visible with traditional clinical inspection

Digital dermoscopic photographs can be viewed and magnified immediately on camera or computer screens

Polarizable elements in scabies infestation: a clue to diagnosis. Foo CW1, Florell SR, Bowen AR

The diagnosis of scabies infestation is straightforward in cases where mite parts are largely visible

However, mites are often not captured in a specimen's planes of section

Polariscopic examination is a fast and simple adjunctive diagnostic tool to light microscopy

We describe the unique polariscopic findings in scabies infestation.

Two cases of crusted scabies and eight cases of typical scabies were subjected to polariscopic examination

Diagnostic mite parts were visualized in at least one section in all cases. Attached and detached spines as well as scybala (fecal material) are polarizable.

Dermoscopy for the in vivo detection of sarcoptes scabiei.

Prins C, Stucki L, French L, Saurat JH, Braun RP.Report of an 80-year-old patient who had intense

pruritus which did not respond to a 3-month treatment with topical corticosteroids

Traditional diagnostic methods for scabies failed On dermoscopy examination of the excoriations we

found the typical dermoscopic aspect of the scabies mite at a distance. Dermoscopy allows identifying a triangular structure which corresponds to the anterior section of the mite including the mouth part and the 2 pairs of front legs. This aspect has been described as resembling a jetliner with its trail, a delta glider or a spermatozoid.

Copyright 2004 S. Karger AG, Basel Skin Lesion Unit, Department of Dermatology, University

Hospital Geneva, Geneva, Switzerland

Traditional diagnostic methods for scabies failed in this case because the mites were at a distance from the burrows.

The diagnosis is frequently missed. Dermoscopy is a useful tool for the diagnosis of scabies either as a diagnostic test or to guide the traditional diagnostic tests.

Scrape or Perish: The importance of skin scraping in erythrodermaMamta V Kamath, Ruchi A Gupta, Nitin Nadkarni, Sham SonavaneDepartment of Dermatology, Rajawadi Hospital, Mumbai and Padmashri Dr. D.Y. Patil Medical College, Navi Mumbai, India

A 65-year-old woman presented with itchy lesions all over the body since 15 years

She had been diagnosed as a case of psoriasis at another center and given topical steroids and emollients

Of late, after an apparent flare of psoriasis, she was also given methotrexate

However, the lesions continued to increase and were accompanied by fever

. Indian Dermatol Online J 2011

Like syphilis, scabies has come to be known as the great imitator

Its spectrum of clinical manifestations may lead the practitioner to the wrong diagnosis

Confirmation of this diagnosis is important

Conclusion

Easily misdiagnosed if not confirmed

Scybala may be the only diagnostic finding!

Kamath MV, Gupta RA, Nadkarni N, Sonavane S. Scrape or Perish: The importance of skin scraping in erythroderma. Indian Dermatol Online J 2011;2:107-8

Norihisa Ishii ,The Japanese Dermatological Association, Tokyo, Japan; 12-13

References

Thank You!