Onychomycosis: Clinical overview and diagnosis

J Am Acad Dermatol. 2019 Apr;80(4):835-851. doi: 10.1016/j.jaad.2018.03.062. Epub 2018 Jun 28.


Onychomycosis is a fungal nail infection caused by dermatophytes, nondermatophytes, and yeast, and is the most common nail disorder seen in clinical practice. It is an important problem because it may cause local pain, paresthesias, difficulties performing activities of daily life, and impair social interactions. In this continuing medical education series we review the epidemiology, risk factors, and clinical presentation of onychomycosis and demonstrate current and emerging diagnostic strategies.

Keywords: Trichophyton rubrum; biofilm; confocal microscopy; dermatophyte; dermoscopy; direct microscopy; fungal culture; fungal nail infection; histopathology; nondermatophyte; onychomycosis; optical coherence tomography; polymerase chain reaction; tinea pedis; yeast.

Publication types

  • Review

MeSH terms

  • Biofilms
  • Dermoscopy
  • Diagnosis, Differential
  • Foot Dermatoses / diagnosis
  • Foot Dermatoses / epidemiology
  • Foot Dermatoses / microbiology
  • Foot Dermatoses / pathology
  • Hand Dermatoses / diagnosis
  • Hand Dermatoses / epidemiology
  • Hand Dermatoses / microbiology
  • Hand Dermatoses / pathology
  • Humans
  • Microscopy, Confocal
  • Mycological Typing Techniques
  • Onychomycosis / diagnosis*
  • Onychomycosis / epidemiology
  • Onychomycosis / microbiology
  • Onychomycosis / pathology
  • Physical Examination
  • Polymerase Chain Reaction
  • Prevalence
  • Risk Factors
  • Tomography, Optical Coherence