A Retrospective Study of Onychomycosis, Clinical Diagnosis Versus Laboratory Diagnosis

Abstract

INTRODUCTION AND OBJECTIVES: Onychomycosis is defined as a fungal infection of the nail usually caused by a dermatophyte. This retrospective study will compare the diagnosis of onychomycosis based on clinical exam findings in comparison to laboratory results. METHODS: Clinical diagnosis of onychomycosis of the nail is made through visual inspection of the nail. The characteristics that define a clinical diagnosis of onychomycosis include but is not limited to: thickness of nail, discoloration (yellow, black, and/or brown), crumbly texture, subungual debris, subungual fluid, splitting of the nail, and/or nail dystrophy. Patients were treated with either a topical or oral drug and this was based solely on the clinical characteristics of the nail with no further lab testing. The most recent 50 charts from the past three years (1/1/2013 to 1/31/2016) were utilized to conduct this retrospective study. The charts were analyzed based on the following criteria: patients that were clinically diagnosed with onychomycosis and also had a positive laboratory results that included a PAS, PCR, or KOH staining. RESULTS: We found that there was a higher incidence of clinically positive diagnosis vs. laboratory culture positive results. CONCLUSIONS: As expected fungal nail cultures are sometimes less sensitive than our clinical evaluation. This may be due to false negatives or failure to obtain an adequate sample for culture analysis. This may effect treatment standard of care and accuracy of treatment.