Original article
High accuracy of recognition of common forms of folliculitis by dermoscopy: An observational study

https://doi.org/10.1016/j.jaad.2019.03.054Get rights and content

Background

Clinical differentiation of folliculitis types is challenging. Dermoscopy supports the recognition of folliculitis etiology, but its diagnostic accuracy is not known.

Objective

To assess the diagnostic accuracy of dermoscopy for folliculitis.

Methods

This observational study included patients (N = 240) with folliculitis determined on the basis of clinical and dermoscopic assessments. A dermoscopic image of the most representative lesion was acquired for each patient. Etiology was determined on the basis of cytologic examination, culture, histologic examination, or manual hair removal (when ingrowing hair was detected) by dermatologist A. Dermoscopic images were evaluated according to predefined diagnostic criteria by dermatologist B, who was blinded to the clinical findings. Dermoscopic and definitive diagnoses were compared by dermatologist C.

Results

Of the 240 folliculitis lesions examined, 90% were infections and 10% were noninfectious. Infectious folliculitis was caused by parasites (n = 71), fungi (n = 81), bacteria (n = 57), or 7 viruses (n = 7). Noninfectious folliculitis included pseudofolliculitis (n = 14), folliculitis decalvans (n = 7), and eosinophilic folliculitis (n = 3). The overall accuracy of dermoscopy was 73.7%. Dermoscopy showed good diagnostic accuracy for Demodex (88.1%), scabietic (89.7%), and dermatophytic folliculitis (100%), as well as for pseudofolliculitis (92.8%).

Limitations

The diagnostic value of dermoscopy was calculated only for common folliculitis. Diagnostic reliability could not be calculated.

Conclusion

Dermoscopy is a useful tool for assisting in the diagnosis of some forms of folliculitis.

Section snippets

Patients

Consecutive patients who visited the Dermatology Department of Başkent University Hospital in Adana, Turkey, between November 2012 and November 2018 and in whom folliculitis had been diagnosed on the basis of clinical and dermoscopic assessment (papules or pustules centered around a hair) were considered eligible for the study. The study was reviewed and approved by the institutional review board at the University of Başkent, Ankara, Turkey. The Declaration of Helsinki protocols were followed,

Patients

A total of 240 folliculitis lesions from 240 patients (132 females and 108 males) were included in the study. The mean age of the patients was 28 years (range, 2-76 years). The face was the most common localization of lesions (35%). Other affected areas included the trunk (30.4%), scalp (21.3%), groin (7.5%), and extremities (5.8%). Of the 240 lesions, 216 (90%) lesions were infectious and 24 (10%) were noninfectious (Table I). The definitive diagnosis was made by cytologic analysis (n = 215),

Discussion

In the current study, we investigated the diagnostic value of dermoscopy in the differentiation of folliculitis. We determined the diagnostic accuracy of dermoscopy as 73.7%. The diagnostic accuracy was high in patients with Demodex folliculitis (88.1%), scabies folliculitis (89.7%), and dermatophytic folliculitis (100%).

According to the available literature, bacterial culture, fungal culture, and histopathologic examination are the most common methods used to investigate the causes of

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    Funding sources: None

    Conflicts of interest: None disclosed.

    IRB approval status: This study was reviewed and approved by the institutional review board at the University of Başkent, Ankara, Turkey (KA12/226).

    Reprint requests: Reprints not available from the authors.

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