Skip to main content

Bedside Diagnostic Techniques in Dermatology


Purpose of Review

To review bedside diagnostic techniques in the modern dermatologic landscape.

Recent Findings

Microscopy has been a commonly used bedside technique for the diagnosis of various fungal, parasitic, and bacterial infections. Tzanck smears are another useful technique often used for diagnosing herpesvirus lesions, but evidence shows that its use could be expanded to include other conditions as well. Wood’s light fluorescence is a simple non-invasive technique that has often been utilized to diagnose various bacterial, fungal, and pigmentation disorders, although its list of uses has not been exhausted. Cellophane tape scraping can provide a scalpel-free alternative to traditional scrapings. With the ever-decreasing costs of technologies such as PCR, swabbing for PCR may become a more common method of diagnosing more infectious skin pathologies.


Bedside diagnostic techniques in dermatology are a useful adjunct to the dermatologic physical exam to confirm a diagnosis rapidly, affordably, and accurately.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3


Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance

  1. 1.

    Wanat KA, Dominguez AR, Carter Z, Legua P, Bustamante B, Micheletti RG. Bedside diagnostics in dermatology: Viral, bacterial, and fungal infections. J Am Acad Dermatol. 2017;77(2):197–218.

    Article  PubMed  Google Scholar 

  2. 2.

    Guzman AK, Kaffenberger BH. Office-based dermatologic diagnostic procedure utilization in the United States Medicare population from 2000-2016. Int J Dermatol. 2019;58(11):1317–22.

    Article  PubMed  Google Scholar 

  3. 3.

    Kurade SM, Amladi SA, Miskeen AK. Skin scraping and a potassium hydroxide mount. Indian J Dermatol Venereol Leprol. 2006;72(3):238–41.

    Article  PubMed  Google Scholar 

  4. 4.

    Kelly BP. Superficial fungal infections. Pediatr Rev. 2012;33(4):e22–37.

    Article  PubMed  Google Scholar 

  5. 5.

    Siderits R, Dikon A, Ouattara O, Godyn JJ. Preparation and use of a scabies skin scraping kit. Adv Skin Wound Care. 2006;19(1):22–5.

    Article  Google Scholar 

  6. 6.

    Leung AK, Lam JM, Leong KF, Hon KL. Tinea corporis: an updated review. Drugs Context. 2020;9:1–12.

    Article  Google Scholar 

  7. 7.

    Roberts GD, Yu PKW, Washington JA II. Direct microscopic examination of specimens. In: Laboratory Procedures in Clinical Microbiology. New York, NY: Springer US; 1981. p. 69–89.

    Chapter  Google Scholar 

  8. 8.

    Burke WA. A simple stain for rapid office diagnosis of fungus infections of the skin. Arch Dermatol. 1984;120(11):1519–20.

    CAS  Article  PubMed  Google Scholar 

  9. 9.

    • Micheletti RG, Dominguez AR, Wanat KA. Bedside diagnostics in dermatology: parasitic and noninfectious diseases. J Am Acad Dermatol. 2017;77(2):221–30. review article discusses various bedside techniques including scrapings, skin snips, microscopy, Tzanck smears, swabs, and PCR.

    Article  PubMed  Google Scholar 

  10. 10.

    Ruocco E, Baroni A, Donnarumma G, Ruocco V. Diagnostic procedures in dermatology. Clin Dermatol. 2011;29(5):548–56.

    Article  PubMed  Google Scholar 

  11. 11.

    Feuilhade de Chauvin M. New diagnostic techniques. J Eur Acad Dermatol Venereol. 2005;19(Suppl 1(s1)):20–4.

    Article  PubMed  Google Scholar 

  12. 12.

    Delasco Dermatologic Lab & Supply, Inc. Material safety data sheet: chlorazol fungal stain 2021 Published December 2010. Accessed May 10, 2021.

  13. 13.

    • Marks JG, Miller JJ. Lookingbill and marks’ principles of dermatology. Philadelphia, PA: Elsevier - Health Sciences Division 2019. This dermatology textbook explores numerous facets of the field and provides practical advice on gathering scrapings, performing a Tzanck smear, and swabbing.

  14. 14.

    Sunderkötter C, Feldmeier H, Fölster-Holst R, Geisel B, Klinke-Rehbein S, Nast A, et al. S1 guidelines on the diagnosis and treatment of scabies - short version. J Dtsch Dermatol Ges. 2016 Nov;14(11):1155–67.

    Article  PubMed  Google Scholar 

  15. 15.

    Cohen PR. Classic and non-classic (surrepticius) scabies: Diagnostic and treatment considerations. Cureus. 2020;12(3):e7419.

    PubMed  PubMed Central  Google Scholar 

  16. 16.

    Nicolaidis G, Rosen T, Scabies, Connor DH, Chandler FW, Schartz DA, Manz HJ, Lack EE Pathology of infectious diseases. Stamford, CT: Appleton & Lange 1997

  17. 17.

    Cheng TA, Mzahim B, Koenig KL, Alsugair A, Al-Wabel A, Almutairi BS, et al. Scabies: Application of the novel identify-isolate-inform tool for detection and management. West J Emerg Med. 2020;21(2):191–8.

    Article  Google Scholar 

  18. 18.

    • Raghukumar S, Ravikumar BC. Potassium hydroxide mount with cellophane adhesive tape: a method for direct diagnosis of dermatophyte skin infections. Clin Exp Dermatol. 2018;43(8):895–8. split body study showed that the cellophane tape method is superior to a KOH prep in detecting cutaneous fungal infections.

    CAS  Article  PubMed  Google Scholar 

  19. 19.

    CDC-Centers for Disease Control, Prevention. CDC - Onchocerciasis - resources for health professionals. 2010 [cited 2021 Jun 23]; Available from:

  20. 20.

    Wolff K, Johnson RC, Saavedra A, Roh EK. Fitzpatrick’s color atlas and synopsis of clinical dermatology, eighth edition. 8th ed. McGraw-Hill Education/Medical 2017 How to Use this Book.

  21. 21.

    Ovrén E, Berglund L, Nordlind K, Rollman O. Dermatophytosis: fluorostaining enhances speed and sensitivity in direct microscopy of skin, nail and hair specimens from dermatology outpatients. Mycoses. 2016;59(7):436–41.

    Article  PubMed  Google Scholar 

  22. 22.

    Campos-do-Carmo G, Ramos-e-Silva M. Dermoscopy: basic concepts. Int J Dermatol. 2008;47(7):712–9.

    Article  PubMed  Google Scholar 

  23. 23.

    Kittler H, Pehamberger H, Wolff K, Binder M. Diagnostic accuracy of dermoscopy. Lancet Oncol. 2002;3(3):159–65.

    CAS  Article  PubMed  Google Scholar 

  24. 24.

    Menzies SW. Evidence-based dermoscopy. Dermatol Clin. 2013;31(4):521–4, vii.

    CAS  Article  PubMed  Google Scholar 

  25. 25.

    Olszewska M, Rudnicka L, Rakowska A, Kowalska-Oledzka E, Slowinska M. Trichoscopy. Arch Dermatol. 2008;144(8):1007.

    Article  PubMed  Google Scholar 

  26. 26.

    Miteva M, Tosti A. Hair and scalp dermatoscopy. J Am Acad Dermatol. 2012;67(5):1040–8.

    Article  PubMed  Google Scholar 

  27. 27.

    Rudnicka L, Rakowska A, Olszewska M. Trichoscopy: how it may help the clinician. Dermatol Clin. 2013;31(1):29–41.

    CAS  Article  PubMed  Google Scholar 

  28. 28.

    Alessandrini A, Starace M, Bruni F, Piraccini BM. Bubble hair and the usefulness of trichoscopy. Dermatol Pract Concept. 2020;10(4):e2020081.

    Article  PubMed  PubMed Central  Google Scholar 

  29. 29.

    Widaty S, Pusponegoro EH, Rahmayunita G, Astriningrum R, Akhmad AM, Oktarina C, et al. Applicability of trichoscopy in scalp seborrheic dermatitis. Int J Trichology. 2019;11(2):43–8.

    Article  PubMed  PubMed Central  Google Scholar 

  30. 30.

    Fox G. Diagnosis of scabies by dermoscopy. BMJ Case Rep. 2009:bcr0620080279.

  31. 31.

    Li F-Z, Chen S. Diagnostic accuracy of dermoscopy for scabies. Korean J Parasitol. 2020;58(6):669–74.

    Article  PubMed  PubMed Central  Google Scholar 

  32. 32.

    • Yamamoto T, Aoyama Y. Detection of multinucleated giant cells in differentiated keratinocytes with herpes simplex virus and varicella zoster virus infections by modified Tzanck smear method. J Dermatol. 2021;48(1):21–7. experimental study suggests a new method of increasing the sensitivity of discovering multinucleated giant cells in suspected herpetic lesions.

    CAS  Article  PubMed  Google Scholar 

  33. 33.

    Panwar H, Joshi D, Goel G, Asati D, Majumdar K, Kapoor N. Diagnostic utility and pitfalls of Tzanck smear cytology in diagnosis of various cutaneous lesions. J Cytol. 2017;34(4):179–82.

    Article  PubMed  PubMed Central  Google Scholar 

  34. 34.

    • Wantavornprasert K, Chottawornsak N, Hurst CP, Asawanonda P, Hansasuta P, Rerknimitr P. A quicker tzanck smear with methylene blue stain for diagnosis of Herpesvirus skin infections: a comparative study of giemsa stain. Jpn J Infect Dis. 2019;72(6):432–4. cross sectional analytical study showed that methylene blue stain can make Tzanck smears quicker than the traditional Giemsa stain.

    CAS  Article  PubMed  Google Scholar 

  35. 35.

    Silverberg NB. Pediatric molluscum: an update. Cutis. 2019;104(5):301–305;E1;E2.

    PubMed  Google Scholar 

  36. 36.

    •• Noyan MA, Durdu M, Eskiocak AH. TzanckNet: a convolutional neural network to identify cells in the cytology of erosive-vesiculobullous diseases. Sci Rep. 2020;10(1):18314. blinded experimental study showed that TzanckNet, a deep learning model, is capable of accurately analyzing hundreds of slides per minutes, which would greatly aid dermatologists and patients.

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  37. 37.

    Al Aboud DM, Gossman W. Woods light. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2021.

    Google Scholar 

  38. 38.

    Rojas Mora E, Freites Martínez A, Hernández-Núñez A, Borbujo MJ. Trichomycosis axillaris: clinical, wood lamp, and dermoscopic diagnostic images. Actas Dermosifiliogr. 2017;108(3):264–5.

    CAS  Article  Google Scholar 

  39. 39.

    Mojeski JA, Almashali M, Jowdy P, Fitzgerald ME, Brady KL, Zeitouni NC, et al. Ultraviolet imaging in dermatology. Photodiagn Photodyn Ther. 2020;30(101743):101743.

    CAS  Article  Google Scholar 

  40. 40.

    Peña-Romero AG, García-Romero MT. Diagnosis and management of linear scleroderma in children. Curr Opin Pediatr. 2019;31(4):482–90.

    CAS  Article  PubMed  Google Scholar 

  41. 41.

    Kromann AB, Ousager LB, Ali IKM, Aydemir N, Bygum A. Pigmentary mosaicism: a review of original literature and recommendations for future handling. Orphanet J Rare Dis. 2018;13(1):39.

    Article  PubMed  PubMed Central  Google Scholar 

  42. 42.

    Sato T, Asahina Y, Toshima S, Yaguchi T, Yamazaki K. Usefulness of Wood’s lamp for the diagnosis and treatment follow-up of onychomycosis. Med Mycol J. 2020;61(2):17–21.

    Article  PubMed  Google Scholar 

  43. 43.

    Blaizot R, Simon S, Ginouves M, Prévot G, Blanchet D, Ravel C, et al. Validation of swab sampling and SYBR green-based real-time PCR for the diagnosis of cutaneous leishmaniasis in French Guiana. J Clin Microbiol. 2021;59(2)

  44. 44.

    Ogai K, Nagase S, Mukai K, Iuchi T, Mori Y, Matsue M, et al. A comparison of techniques for collecting skin microbiome samples: swabbing versus tape-stripping. Front Microbiol. 2018;9:2362.

    Article  PubMed  PubMed Central  Google Scholar 

  45. 45.

    Boom R, Sol CJ, Salimans MM, Jansen CL, Wertheim-van Dillen PM, van der Noordaa J. Rapid and simple method for purification of nucleic acids. J Clin Microbiol. 1990;28(3):495–503.

    CAS  Article  Google Scholar 

  46. 46.

    Jeddi F, Piarroux R, Mary C. Application of the NucliSENS easyMAG system for nucleic acid extraction: optimization of DNA extraction for molecular diagnosis of parasitic and fungal diseases. Parasite. 2013;20:52.

    Article  Google Scholar 

  47. 47.

    CDC’s Division of Parasitic Diseases and Malaria. Practical Guide for Specimen Collection and Reference Diagnosis of Leishmaniasis. Available from:

  48. 48.

    Tajima M, Sugita T, Nishikawa A, Tsuboi R. Molecular analysis of Malassezia microflora in seborrheic dermatitis patients: comparison with other diseases and healthy subjects. J Invest Dermatol. 2008;128(2):345–51.

    CAS  Article  PubMed  Google Scholar 

  49. 49.

    Gupta N. DNA extraction and polymerase chain reaction. J Cytol. 2019;36(2):116–7.

    Article  PubMed  PubMed Central  Google Scholar 

  50. 50.

    Goltz RW. Polymerase chain reaction in dermatology. West J Med. 1994;160(4):362.

    CAS  PubMed  PubMed Central  Google Scholar 

  51. 51.

    Lo AC, Feldman SR. Polymerase chain reaction: Basic concepts and clinical applications in dermatology. J Am Acad Dermatol. 1994;30(2):250–60.

    CAS  Article  PubMed  Google Scholar 

  52. 52.

    Schremser V, Antoniewicz L, Tschachler E, Geusau A. Polymerase chain reaction for the diagnosis of herpesvirus infections in dermatology: analysis of clinical data: Analysis of clinical data. Wien Klin Wochenschr. 2020;132(1–2):35–41.

    CAS  Article  PubMed  Google Scholar 

  53. 53.

    Swick BL. Polymerase chain reaction-based molecular diagnosis of cutaneous infections in dermatopathology. Semin Cutan Med Surg. 2012;31(4):241–6.

    CAS  Article  PubMed  Google Scholar 

  54. 54.

    Sullivan M, Sams R II, Jamieson B, Holt J. Clinical inquiries. What is the best test to detect herpes in skin lesions? J Fam Pract. 2006;55(4):346–8.

    PubMed  Google Scholar 

  55. 55.

    Moreira OC, Yadon ZE, Cupolillo E. The applicability of real-time PCR in the diagnostic of cutaneous leishmaniasis and parasite quantification for clinical management: current status and perspectives. Acta Trop. 2018;184:29–37.

    CAS  Article  PubMed  Google Scholar 

  56. 56.

    Paulino LC, Tseng C-H, Strober BE, Blaser MJ. Molecular analysis of fungal microbiota in samples from healthy human skin and psoriatic lesions. J Clin Microbiol. 2006;44(8):2933–41.

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  57. 57.

    Mimori T, Matsumoto T, Calvopiña MH, Gomez EA, Saya H, Katakura K, et al. Usefulness of sampling with cotton swab for PCR-diagnosis of cutaneous leishmaniasis in the New World. Acta Trop. 2002;81(3):197–202.

    CAS  Article  PubMed  Google Scholar 

  58. 58.

    Delaunay P, Hérissé AL, Hasseine L, Chiaverini C, Tran A, Mary C, et al. Scabies polymerase chain reaction with standardized dry swab sampling: an easy tool for cluster diagnosis of human scabies. Br J Dermatol. 2020;182(1):197–201.

    CAS  Article  PubMed  Google Scholar 

  59. 59.

    Gustafson E, Bakotic W, Bennett L, Page L, McCarthy L. DNA-based detection for onychomycosis correlates better to histopathology than does fungal culture. Dermatol Online J. 2019;25(7)

  60. 60.

    Uppal SK, Beer J, Hadeler E, Gitlow H, Nouri K. The clinical utility of teledermoscopy in the era of telemedicine. Dermatol Ther. 2021:e14766.

Download references

Author information




All authors contributed to the preparation of this manuscript.

Corresponding author

Correspondence to John C. L. Trinidad.

Ethics declarations

Conflict of Interest

None declared.

Human and Animal Rights and Informed Consent

This article does not contain any studies with human or animal subjects performed by any of the authors.

Additional information

IRB Statement

This study was deemed exempt by the Institutional Review Board at the Ohio State University.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

This article is part of the Topical Collection on Hospital-based Dermatology

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Goldenberg, M., Liao, YT., Libson, K. et al. Bedside Diagnostic Techniques in Dermatology. Curr Derm Rep (2021).

Download citation


  • Bedside diagnostics
  • Dermatology
  • Scrapings
  • Tzanck smear
  • Dermoscopy
  • Microscopy