–Onychomycosis is the most prevalent nail disease.amounting to about 50% of all onychopathies .The diagnosis is still a challenge considering that the gold standard complementary test (direct microscopy and culture) may be false negative in up to 35% of the cases.
•Materiel and methodes :
–We have performed a dermoscopic study in a serie of 57 cases in our consultation for nail diseases. The Purpose of the study was to Study of the sensitivity ,specificity and positive predictive value of dermoscopic signs in the diagnosis of onychomycosis ;it was a Cross-sectional study conducted in our dermatology department at Hassan second University Hospital Over a period of one year from June 2014 to June 2015
–57 cases have been collected .Sex ratio F / M was 1.6 (63,2%F ,36,8% M). The average age was 45 years.Mycological examination found Trichophyton in 44 cases (77%) (88% T richophyton rubrum TR) .Candida albicans CA in 14 cases (22%).Microsporum gypsum 1case (1%) .The dermoscopic signs of onychomycosis with trichophyton were Subungual hyperkeratosis with ruins aspect in 84% Pachyonychia in 75% .Longitudinal white -yellow streaks in 63% .Onycholysis found in 54% .In addition the dermoscopic signs found in candida’s onychomycosis were: Nail hyperkeratosis with ruins aspect found in 85.7% .Pachyonychia in 71.4% . In trichophyton the sensitivity of xanthonychia was 90,7%, longitudinal yellow streaks was 81,4%, pachyonychia 83,7% . The specificity was higher in melanonychia 85,7% ,beau ‘s lines 91,7% . The Positive predictive value of melanonychia was 86,7%,dermatophytoma 84,2%, pachyonychia 83,7% .In candida s,the sensitivity of onychorrhexis was 80,0% ,subungual hyperkeratosis 73,3% . The specificity 100% of paronychia, chloronychia 97,6%,leukonychia 95,2% the Positive predictive value was 100% with paronychia 85,7% with chloronychie
•Onychomycosis is a disease that the dermatologist is faced with great frequency, representing approximately 50% of nail affections.
•The clinical picture is a critical element for establishing the diagnosis, although it may be insufficient
•The dermoscopic signs may be useful in confirming the diagnostic suspicion of onychomycosis when it is not possible to perform tests that are more specific.
•Our study shows the usefulness of dermoscopy as a diagnostic tool for the diagnosis of onychomycosis.
•We recommend future studies with homogeneous groups of different clinical subtypes of onychomycosis and including patients with suspected traumatic onycholysis or other nail diseases.
•Our results are preliminary, there will be completed by increase the number of patients for more validation.
•By showing the importance of dermoscopy in the diagnostic investigation .It can be used to follow-up of onychomycosis treatment .We think that this study will contribute to daily dermatological practice, even though more studies are required to confirm our findings.