Polarizable elements in scabies infestation: a clue to diagnosis

Abstract

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. Specifically, spines show a polarizable outer sheath with dark central core while scybala show peripherally concentrated, stippled birefringence. Similar stippled birefringence is visible within the gut of some mites whereas significant birefringence is not appreciated in other mite parts. These results suggest that polariscopic examination is a helpful clue in the diagnosis of scabies infestation, especially in cases where the body of the mite is not visualized.

‘Hints’ in the horn: diagnostic clues in the stratum corneum

“…In addition, it has been found that some mite parts, including attached and detached spines, and scybala (fecal material), are birefringent under examination with polarized light, making this a potential adjunct in the diagnosis of scabies. More precisely, scabetic spines may be circular on cross section and show a central dark core with peripheral birefringence, whereas scybala exhibit stippled birefringence …”

“…More precisely, scabetic spines may be circular on cross section and show a central dark core with peripheral birefringence, whereas scybala exhibit stippled birefringence. 97 If the mite is present, one can observe dermoscopically a small brown triangle at the end of the curved and scaly burrow, which corresponds to the anterior part of the mite (Fig. 16).…”

Infectious Diseases and Infestations of the Vulva

“…6.31b ). Scabietic spines are circular on cross section, with polarize light they show dark center and peripheral birefringence [ 131 ]. Eggs can be detected in the burrows as small geometric round to oval structures with few organelles; after hatching, the remnants simulate "pigtails" (Fig.…”

Pulse granuloma of the lip: morphologic clues in its differential diagnosis

“…In our opinion, the birefringence of amorphous pigmented fragments points to vegetable pericarp rather than to animal parts. However, it should be remembered that birefringent spikes have been described in animal organisms seen in cutaneous pathology, such as Demodex or Sarcoptes . In addition, it should be recalled that not all arthropods have a spiculated cuticle.…”

“…However, it should be remembered that birefringent spikes have been described in animal organisms seen in cutaneous pathology, such as Demodex or Sarcoptes. 42 In addition, it should be recalled that not all arthropods have a spiculated cuticle. For example, Tunga penetrans, which is occasionally seen as a cause of cutaneous infestation, has a cuticle without spines.…”