Differences between polarized and non polarized dermoscopy

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Main PagePrinciples of dermoscopyDifferences between polarized and non polarized dermoscopy
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 Authored by: Florentia Dimitriou     ·  Alon Scope     ·  Ralph P. Braun

 Keywords:   polarized light · non polarized light · dermoscopy
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Description Describes the differences between polarized and non polarized dermoscopyThe examination of [skin lesions] with a 'dermatoscope'. This traditionally consists of a magnifier (typically x10), a non-polarised light source, a transparent plate and a liquid medium between the instrument and the skin, and allows inspection of skin lesions unobstructed by skin surface reflections. Modern dermatoscopes dispense with the use of liquid medium and instead use polarised light to cancel out skin surface reflections.
Author(s) Florentia Dimitriou · Alon Scope · Ralph P. Braun
Owner Alon Scope→ send e-mail
Status released
Status update July 2, 2018
Status by Ralph P. Braun


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The main difference between non-polarized dermoscopy (NPD) and polarized dermoscopy (PD) is the depth of visualized structuresThis glossary term has not yet been described.. While NPD is better for inspecting structures in the superficialThis glossary term has not yet been described. skin layers (e.g., superficial epidermis down to the dermo-epidermal junction [DEJ]), PD is better for evaluating the deeper skin layers (e.g., DEJ and superficial dermis).

For example, both Milia-like cysts and blue-white veil are caused by superficial changes in the epidermis and are therefore better visualized with NPD. On the other hand, Shiny white structures (chrysalis/crystalline, blotches and strands, rosettesFour bright white dots or clods arranged together as a square (or a four leaf clover)) are better visualized with PD since they are associated with increased collagen at the superficial dermis. In addition, polarized lightThis glossary term has not yet been described. rapidly randomizes its polarization when it encounters a birefringent structure, such as collagen.

Additional difference between NPD and PD

  • Since PD does not require direct skin contact, blood vesselsare the part of the circulatory system, and microcirculation, that transports blood throughout the human body and pink colorColor (American English) or colour (Commonwealth English) is the characteristic of human visual perception described through color categories, with names such as red, yellow, purple, or blue. (vascular blush) are more evident under PD (due to lack of pressure effect). In addition, blood vessels are located in the dermis that is better visualized with PD.
  • In pigmented lesions with melanin at the DEJ (e.g.. junctional neviThis glossary term has not yet been described.) or superficial dermis (e.g. blue nevi), PD will show slightly darker shades of brown and blue, and sometimes more variability in pigmentation, compared with NPD.

Diagnostic accuracyThis glossary term has not yet been described.

The differences between PD and NPD may impact the diagnostic accuracyThis glossary term has not yet been described. and diagnostic confidence level. For example, PD can increase sensitivityThis glossary term has not yet been described. for detecting amelanotic melanomas or structure-poor melanomas and basal cell carcinomas, because PD highlights the presence of blood vessels, vascular blush, and/or white shiny lines (chrysalis/crystalline). In contrast, NPD can increase specificityThis glossary term has not yet been described. by allowing to correctly identify Milia-like cysts and comedo like openings in seborrheic keratoses.
”Hybrid” dermoscopes toggle between PD and NPD modes. These hybrid devices can enhance dermoscopic diagnosisis the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines with variations in the use of logic, analytics, and experience to determine "cause and effect". In systems engineering and computer science, it is typically used to determine the causes of symptoms, mitigations, and solutions because PD and NPD provide complementary information. These devices should always be in direct contact with the skin and used with a liquid interface, otherwise dermoscopic structuresThis glossary term has not yet been described. will only be visualized in PD mode.


ColorsThis glossary term has not yet been described. and structures NPD PD
Melanin + ++
Red/pink + +++
Blue-white due to orthokeratosis +++ +
Blue-white due to regressionThis glossary term has not yet been described. +++ ++
PepperingGray dots +++ ++
Chrysalis or white scar +/− +++
VesselsThis glossary term has not yet been described. + +++
Milia-like cystWhite to yellowish round opalescent structures corresponding to intraepidermal cysts. When they are small and bright they are called starry. When they are larger and less bright they are called cloudy. +++ +/−




ReferencesThis is material contained in a footnote or bibliography holding further information.
  1. An Atlas of DermoscopyThe examination of [skin lesions] with a 'dermatoscope'. This traditionally consists of a magnifier (typically x10), a non-polarised light source, a transparent plate and a liquid medium between the instrument and the skin, and allows inspection of skin lesions unobstructed by skin surface reflections. Modern dermatoscopes dispense with the use of liquid medium and instead use polarised light to cancel out skin surface reflections., Second Edition. Marghoob A. et al. CRC Press; 2012.
  2. Agero, A.L., Taliercio, S., Dusza, S.W., Salaro, C., Chu, P. & Marghoob, A.A., 2006, Conventional and polarized dermoscopy features of dermatofibromaDermatofibromas are hard solitary slow-growing papules (rounded bumps) that may appear in a variety of colours, usually brownish to tan; they are often elevated or pedunculated. A dermatofibroma is associated with the dimple sign; by applying lateral pressure, there is a central depression of the dermatofibroma.. Arch Dermatol, 142, 1431–7.
  3. Anderson, R.R. & Parrish, J.A., 1981, The optics of human skinThis glossary term has not yet been described.. J Invest Dermatol, 77, 13–19.
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  6. Benvenuto-Andrade, C., Dusza, S.W., Hay, J.L., Agero, A.L., Halpern, A.C., Kopf, A.W. & Marghoob, A.A., 2006, Level of confidence in diagnosis: clinical examinationThis glossary term has not yet been described. versus dermoscopy examination. Dermatol Surg, 32, 738–44.
  7. Gewirtzman, A.J., Saurat, J.H. & Braun, R.P., 2003, An evaluation of dermoscopy fluids and application techniques. Br J Dermatol, 149, 59–63.
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  10. MacKie, R.M., 1971, An aid to the preoperative assessment of pigmented lesions of the skin. Br J Dermatol, 85, 232–8.
  11. MacKie, R.M., 1972, Cutaneous microscopy in vivo as an aid to preoperative assessment of pigmented lesions of the skin. Br J Plast Surg, 25, 123–9.
  12. Marghoob, A.A., Cowell, L., Kopf, A.W. & Scope, A., 2009, Observation of chrysalis structuresolt term for Chrysalis / Cristalline Structures with polarized dermoscopy. Arch Dermatol, 145, 618.
  13. Pan, Y., Gareau, D.S., Scope, A., Rajadhyaksha, M., Mullani, N.A. & Marghoob, A.A., 2008, Polarized and nonpolarized dermoscopy: the explanation for the observed differences. Arch Dermatol, 144, 828–9.
  14. Ronger, S., Touzet, S., Ligeron, C., Balme, B., Viallard, A.M., Barrut, D., Colin, C. & Thomas, L., 2002, Dermoscopic examination of nailThis glossary term has not yet been described. pigmentation. Arch Derma- tol, 138, 1327–33.
  15. Stauffer, F., Kittler, H., Forstinger, C. & Binder, M., 2001, The dermatoscopeThis traditionally consists of a magnifier (typically x10), a non-polarised light source, a transparent plate and a liquid medium between the instrument and the skin, and allows inspection of skin lesions unobstructed by skin surface reflections. Modern dermatoscopes dispense with the use of liquid medium and instead use polarised light to cancel out skin surface reflections.: a potential source of nosocomial infection? MelanomaThis glossary term has not yet been described. Res, 11, 153–6.
  16. Wang, S.Q., Dusza, S.W., Scope, A., Braun, R.P., Kopf, A.W. & Marghoob, A.A., 2008, Differences in dermoscopic imagesA representation of a person, animal or thing, photographed, painted or otherwise made visible. from nonpolarized dermoscope and polarized dermoscope influence the diagnostic accuracy and confidence level: a pilot study. Dermatol Surg, 34, 1389–95.