Microscopically differentiating dermatophytes from sock fibers

J Am Acad Dermatol. 2009 Dec;61(6):1024-7. doi: 10.1016/j.jaad.2008.11.010.


Background: Dermatophytes are responsible for a number of superficial fungal infections that affect millions worldwide. During microscopic observation a potassium hydroxide (KOH) fungal smear, various filamentous materials such as common textile fibers from socks can obfuscate proper discernment of dermatophytes.

Objective: To differentiate dermatophytes from 9 common sock fibers.

Methods: Nine different textile fiber samples were microscopically analyzed by using a KOH direct smear test; their defining structural features were compared and contrasted with those of dermatophytes.

Results: Although there are several similarities, sock fibers tend to have a non-septate, uniform structure which differentiates them from dermatophytes. Sock fibers are also significantly larger than dermatophytes and can be viewed better at lower magnifications.

Limitations: There is a lack of sock samples with 100% textile fiber composition. Also, fibers were examined in a clean setting, without the detritus that normally accompanies dermatophytes in a clinical setting.

Conclusion: While textile fibers may be present in KOH preparations, their general appearance typically differs from that of dermatophytes; an observer who is familiar with these distinctions will be able to differentiate between the two.

Publication types

  • Comparative Study

MeSH terms

  • Arthrodermataceae / isolation & purification*
  • Clothing*
  • Dermatomycoses / microbiology*
  • Diagnosis, Differential
  • Foot Dermatoses / microbiology*
  • Humans
  • Hydroxides
  • Indicators and Reagents
  • Mycology / methods
  • Potassium Compounds
  • Skin / microbiology*
  • Specimen Handling
  • Textiles / microbiology*


  • Hydroxides
  • Indicators and Reagents
  • Potassium Compounds
  • potassium hydroxide