Onychomycosis in patients with chronic leg ulcer and toenail abnormalities

Global prevalence of onychomycosis in general and special populations: An updated perspective

BACKGROUND

Onychomycosis is a chronic nail disorder commonly seen by healthcare providers; toenail involvement in particular presents a treatment challenge.

OBJECTIVE

To provide an updated estimate on the prevalence of toenail onychomycosis.

METHODS

We conducted a literature search using PubMed, Embase and Web of Science. Studies reporting mycology-confirmed diagnoses were included and stratified into (a) populations-based studies, and studies that included (b) clinically un-suspected and (c) clinically suspected patients.

RESULTS

A total of 108 studies were included. Based on studies that examined clinically un-suspected patients (i.e., with or without clinical features suggestive of onychomycosis), the pooled prevalence rate of toenail onychomycosis caused by dermatophytes was 4% (95% CI: 3-5) among the general population; special populations with a heightened risk include knee osteoarthritis patients (RR: 14.6 [95% CI: 13.0-16.5]), chronic venous disease patients (RR: 5.6 [95% CI: 3.7-8.1]), renal transplant patients (RR: 4.7 [95% CI: 3.3-6.5]), geriatric patients (RR: 4.7 [95% CI: 4.4-4.9]), HIV-positive patients (RR: 3.7 [95% CI: 2.9-4.7]), lupus erythematosus patients (RR: 3.1 [95% CI: 1.2-6.3]), diabetic patients (RR: 2.8 [95% CI: 2.4-3.3]) and hemodialysis patients (RR: 2.8 [95% CI: 1.9-4.0]). The prevalence of onychomycosis in clinically suspected patients was significantly higher likely due to sampling bias. A high degree of variability was found in a limited number of population-based studies indicating that certain pockets of the population may be more predisposed to onychomycosis. The diagnosis of non-dermatophyte mould onychomycosis requires repeat sampling to rule out contaminants or commensal organisms; a significant difference was found between studies that performed single sampling versus repeat sampling. The advent of PCR diagnosis results in improved detection rates for dermatophytes compared to culture.

CONCLUSION

Onychomycosis is an underrecognized healthcare burden. Further population-based studies using standardized PCR methods are warranted.

Literaturübersicht zu Veränderungen der Zehennägel bei chronischer venöser Insuffizienz

Das Patientenkollektiv einer phlebologischen Sprechstunde weist häufig pathologisch veränderte Zehennägel auf. Es stellt sich die Frage, ob ein Zusammenhang zwischen chronischer venöser Insuffizienz und einer Onychodystrophie besteht. Denkbar sind sowohl nichtmykotische Nagelwachstumsstörungen als auch eine Prädisposition für Onychomykosen durch eine Minderperfusion im Rahmen der venösen Insuffizienz. Die wenige Literatur, die es zu dieser Thematik gibt, zeigt unterschiedliche Ergebnisse, welche hier genauer erläutert werden.

Prevalence of Onychomycosis in Diabetic Patients: A Case-Control Study Performed at University Hospital Policlinico in Catania

Diabetes is characterized by an increased rate of serum glucose due to defects in insulin secretion, insulin action or both conditions. Glucose excesses can lead to extended cellular damage, with the consequence of several infectious and non-infectious skin disorders. The aim of the present study was to evaluate the toenail onychomycosis incidence in diabetic patients and healthy ones. The non-interventional, retrospective study was performed at the mycology laboratory of the University hospital “Policlinico-San Marco” in Catania, Italy, for over one year. Nail clippings were collected to perform microscopic and cultural exams, which allowed for the identification of fungal aetiological agents. A total of 715 patients (47 diabetic and 668 non-diabetic patients) were enrolled. In diabetic patients, dermatophytes were the most common cultural isolates (50%), followed by yeasts and moulds in 30.8% and 19.2%, respectively. In non-diabetic patients, the distribution of dermatophytes, yeasts and non-dermatophytic moulds was 67.4%, 5.3% and 27.3%, respectively. According to our results, diabetic patients are more predisposed to nail fungal infection. Our data suggest that dermatological follow-ups should always be performed for diabetic patients. All skin and nail disorders should be carefully monitored to perform a diagnostic confirmation and correct management of diabetic patients.

Prevalence of Onychomycosis among Patients with Transverse Overcurvature of the Nail: Results of a Cross-Sectional Study

Introduction

Transverse overcurvature of the nail (TON) represents one of the main reasons for dermatological consultations due to nail conditions. Association between TON and subungual hyperkeratosis is common and simulates onychomycosis, constituting a difficult differential diagnosis by clinical features. Many cases are treated in daily practice with antifungal therapy even without mycological confirmation. The aim of this study was to determine the prevalence of onychomycosis among patients with TON associated with subungual hyperkeratosis.

Methods

All subjects with clinical diagnosis of TON and subungual hyperkeratosis were subjected to a thorough clinical history, detailed clinical examination, digital photography, and collection of nail clipping and subungual debris for histopathological and microbiological examination (direct microscopy).

Results

Sixty-five samples were collected from 62 female (95.4%) and 3 male (4.6%) participants. Age range was between 34 and 83 years (mean age, 61.2 years). Twenty-eight samples were positive for onychomycosis, giving a 43.07% prevalence rate of onychomycosis among TON associated with hyperkeratosis.

Discussion/Conclusion

According to our data, the prevalence of onychomycosis in patients with TON associated with subungual hyperkeratosis was 43.07%, confirming the need to rule out fungal infection in TON associated with subungual hyperkeratosis prior to considering any unnecessary antifungal treatment.

Toenail alterations in chronic venous disease patients are not always of mycotic origin

Objective

The prevalence of toenail alterations in chronic venous disease has only rarely been studied. We aimed to establish the frequency and clinical characteristics of toenail onychomycosis in chronic venous disease.

Methods

We included 80 adult patients, in all stages of chronic venous disease. Onychomycosis was confirmed by mycological examination. The clinical type of onychomycosis and the onychomycosis severity index were determined. Clinical characteristics of non-fungal nail changes were also analyzed.

Results

We included 58 women and 22 men, with a mean age of 67.0 years. Pathological toenail changes were observed in 83.8% of patients. Onychomycosis was confirmed in 33.8% of all patients and was more frequent in higher clinical stages of chronic venous disease (p = 0.009). Trichophyton rubrum was the leading causative pathogen. Disto-lateral onychomycosis was most commonly present. Average onychomycosis severity index was 23.1.

Conclusion

Onychomycosis accounted for 40% of all toenail alterations. Patients with chronic venous disease often have severe and difficult to treat toenail onychomycosis.