DERMATOSCOPY: Evaluation of Isolated and Combined Patterns in Dermatophytes Onychomycosis
Name: SHIMENA GUISSO CABRAL BUSSATTO
Publication date: 18/12/2018
Examining board:
Name |
Role |
|---|---|
| FAUSTO EDMUNDO LIMA PEREIRA | Internal Examiner * |
Summary: Introduction: Dermoscopy is a method used in the clinical diagnosis of nail melanocytic
lesions, and over the years it has also been used to evaluate inflammatory, immunological and
infectious diseases of the nail, such as fungal infections. Dermoscopy is a useful tool in the
diagnosis of onychomycosis, allowing a comprehensive analysis of the nail apparatus, which is
a low cost exam and easy perform. However, diagnosis of onychomycosis is made through
clinical examination and complemented by mycological exams (DME and culture), being that
histology is recommended in cases of negative mycological exams. Objectives: The aim of this
study is to evaluate the dermatoscopic patterns in cases of dermatophytic onychomycosis.
Patients and methods: Eighty patients with clinical suspicion of onychomycosis on the first
toe were evaluated, in which dermoscopic examination was performed. The technique used to
identify fungi was direct mycological examination. Results: DME was positive for
dermatophyte filamentous fungi in 56 patients (70%) and negative in 24 (30%). Patients who
presented nail abnormalities for a period of more than five years were more prone to the
diagnosis of onychomycosis (p = 0.001). The time of nail changes in patients with
onychomycosis was seven and a half years, and of three years for patients without this
diagnosis, demonstrating the chronic aspect of this infection. The dermatoscopic patterns found
as dermatophytic onychomycosis predictors were: "cut edge" pattern (p = 0.003), longitudinal
striae (p = 0.019), subungual "ruin" hyperkeratosis (p = 0.001), and yellow cromonychia (p =
0.002). Sensitivity (S) and specificity (E) of isolated dermoscopic findings were respectively:
(64.3%, 54.2%) for the "trimmed edge" pattern, (73.2%, 54.2%) for longitudinal striae pattern,
(85.7%, 50%) for subungual "ruin" hyperkeratosis and (78.6%; 58.3%) for yellow
cromonychia. When the patterns were combined, sensitivity and specificity were: (58.9%,
70.8%) for cut edge and longitudinal striae, (62.5%, 66.7%) for longitudinal striae and
subungual "ruin" hyperkeratosis, (51.8%, 75%) for the combination of cut edge, longitudinal
striae and subungual "ruin" hyperkeratosis and finally, (67.9%; 83.3%) for subungual "ruin"
hyperkeratosis and yellow cromonychia. Conclusions: The dermatoscopic patterns found were:
"trimmed edge" pattern, longitudinal striae, yellow cromonychia and subungual "ruin"
hyperkeratosis. The sensitivity of these patterns in patients with positive DME was low, except
for the subungual "ruin" hyperkeratosis, which presented a sensitivity of 85.7%.
When the dermatoscopic patterns were evaluated in a combination way, there was an increase
in the specificity for the diagnosis of dermatophytic onychomycosis in all combinations when
compared with the patterns evaluated in isolation. The association of subungual "ruin"
hyperkeratosis with yellow cromonychia was the most specific (83.3%), demonstrating an
increased specificity in the diagnosis of fungal nail infection when two or more dermatoscopic
predicting onychomycosis findings are present at the examination.
Keywords: Onychomycosis; Dermatophytosis; Dermatoscopy.
