Commentary: onychomycosis: an epidemio-etiologic perspective

Non-Dermatophyte Mold Dominated Onychomycosis in Patients Attending a Rank Higher Specialized Dermatology Clinic in Addis Ababa, Ethiopia

Background

Onychomycosis is a common refractory fungal infection associated with significant morbidity. The objective of this study was to determine the prevalence of onychomycosis, and the diversity and species composition of fungal etiological agents.

Materials and Methods

A clinic-based, prospective, non-randomized cross-sectional study was carried out between October 2018 and June 2019 at Rank Higher Specialized Dermatology Clinic, Addis Ababa, Ethiopia. Nail scrapings were collected aseptically from 200 patients clinically identified with nail disorders of fungal origin by dermatologists. Fungal etiological agents were identified microscopically and by culture method following standard procedures.

Results

Among 200 nail scrapings, 161 (80.5%) samples were found out to be culture positive. Of these, 135 (83.9%) samples yielded single colonies while 26 (16.1%) mixed colonies gave a total of 190 isolates. Among the isolates, 25.8% were dermatophytes while 61.1% were non- dermatophytes molds, and 13.1% were yeasts. Females were more likely to present dystrophic nails than men. Patients in the middle age group were more affected. Trichophyton interdigitale, Aspergillus spp, and Candida albicans were the dominant species.

Conclusion

The prevalence rate of onychomycosis in the present study was high. The isolation rate of non-dermatophyte molds was higher than dermatophytes and yeasts. Trichophyton interdigitale, Aspergillus spp, and Candida albicans were the dominant etiological agents. Females and patients in the middle age group were more affected. An increase in the prevalence of non-dermatophyte molds in nail infections dictates further investigation demonstrating how this group of fungi causes onychomycosis.

A systematic review and meta-analysis on the epidemiology, casual agents and demographic characteristics of onychomycosis in Iran

Onychomycosis or fungal nail infection is one of the most common fungal infections. Nearly 50% of all nail disorders are caused by fungi. This systematic review and meta-analysis was conducted to determine the prevalence of onychomycosis across Iran. We searched English and Persian databases for studies reporting the epidemiologic features of onychomycosis in Iranian people from January 2000 to December 2018. Literature search revealed 307 studies, of which 24 studies met the eligibility criteria. In order to identifying the existence of publication bias among studies, funnel plots were used. The results of the meta-analysis were visualized as a forest plot representing the prevalence estimates of each study. Heterogeneity was also analyzed using the I², Chi², and Tau² statistics. A high level of I² and Chi² was obtained among studies, which provides evidence of notable heterogeneity between studies. The results of current study revealed that the highest prevalence of onychomycosis was related to Mazandaran and Tehran provinces, respectively. As in the literature hypothesized shift in etiologic agents from yeasts to dermatophytes or molds could not be confirmed. Females were affected more frequently than males and in both sexes the highest incidence of infection occurrence was at the ages of >50 years. It seems the highest prevalence of onychomycosis in Mazandaran and Tehran provinces is due to the concentration of specialist doctors and research centers in these two provinces compared with others which leads to more detection and more care of the disease. Therefore, further educational strategies in order to accurate diagnosis in other provinces is necessary to reduce the risk of onychomycosis in Iran.

Prevalence, Risk Factors, and Spectrum of Fungi in Patients with Onychomycosis in Addis Ababa, Ethiopia: A Prospective Study

BACKGROUND

Onychomycosis is a common refractory infection deleteriously affecting quality of life via social stigma and upsetting day-to-day activities.

OBJECTIVE

To study the prevalence of onychomycosis, spectrum of fungal etiological agents, and associated risk factors.

METHODS

A prospective nonrandomized study on the prevalence of onychomycosis was carried out from September 2017 to April 2018 at a dermatology center in Addis Ababa. Nail scrapings were collected from 303 patients clinically identified with nail disorders of fungal origin by dermatologists. Fungal etiological agents were identified microscopically and by culture method following standard procedures.

RESULTS

The prevalence of onychomycosis was 60.4%. Fungi neither were detected nor showed visible fungal growth in 39.6% of the cases. Females were more likely to present dystrophic nails than men. Patients in the middle age group were more affected. The isolation rates of dermatophytes, yeasts, and nondermatophyte molds were 44.7%, 33.3%, and 32.3%, respectively. Trichophyton rubrum, Scytalidium dimidiatum, and Candida albicans were the dominant species of dermatophytes, nondermatophyte molds, and yeasts, respectively. There was no statistically significant association between onychomycosis and risk factors.

CONCLUSIONS

The prevalence rate of onychomycosis in the present study was high. The isolation rate of nondermatophyte molds was comparable with that of dermatophytes. Further studies on the prevalence of onychomycosis, fungal etiological agents, and changes in species distribution of the etiological agents of nail infection in Ethiopia are important.

Epidemiological and Mycological Aspects of Onychomycosis in Dakar (Senegal)

Onychomycosis is a fungal nails infection often caused by yeasts, dermatophytes and molds. It is an important public health concern due to its high prevalence, the problem of diagnostics, and the poor response to treatments. The objective of this study was to evaluate the epidemiological and microbiological profile of onychomycosis diagnosed at the Laboratory of Parasitology-Mycology of the National University Hospital of Fann in Dakar, Senegal, from 2012 to 2016. A retrospective and descriptive study was performed from January 2012 to December 2016 in a patient attending the laboratory of Parasitology-Mycology at the Fann teaching hospital. Socio-demographic, clinical and biological data were collected from the bench registers. Samples from the lesions were tested using direct microscopy and cultured on a Sabouraud-Chloramphenicol and Sabouraud-Chloramphenicol-Actidione medium. A descriptive analysis was done using Stata IC 12 software. The significance level of different tests was set at 5% two-side. A total of 469 patients were included in this study. The mean age of the study population was 33.2 ± 15.2 years, and the sex ratio was 0.52. The prevalence of onychomycosis was 48.4% (227/469). The main clinical presentations were disto-lateral subungual onychomycosis (37.9%) and onyxis (46.5%). Identified fungal species were Candida albicans (42.7%), Candida spp. (39.5%), Trichophyton soudanense (10.1%), Fusarium spp. (5.3%), and Candida tropicalis (2.6%). Candida albicans was more frequent in subjects over 15 years of age (43.6%) and women (45%). However, Trichophyton soudanense was higher in patients under 15 years old (17.4%) as well as in male subjects (18.8%). In conclusion, onychomycosis is a common cause of consultation in health facilities. Candida albicans and Trichophyton Soudanense are the main fungal species causing onychomycosis. A better understanding of the epidemiology of onychomycosis as well as the spectrum of the pathogen could contribute to improve the management of the infection.

A Population-based study of Toenail onychomycosis in Israeli children

Onychomycosis is widespread in the adult population, but considered to be rare in children. A number of studies in recent years show a rise in the prevalence of toenail onychomycosis in children. Of these, only a few were population-based. Here, we present a comprehensive cross-sectional population-based survey of toenail onychomycosis in primary school children in Israel. The survey included 1148 children, 598 boys, and 550 girls aged 5 to 14 from primary schools in the Jerusalem vicinity. Each child underwent a physical examination and completed a personal questionnaire, which provided background information of predisposing factors. The survey shows a prevalence of 0.87% of toenail onychomycosis. Although this figure is too small for statistical analysis, some important conclusions could be drawn: prevalence increased with age: boy/girl ratio was 2.2; the dominant etiologic agent was Trichophyton rubrum followed by Trichophyton mentagrophytes and Candida albicans. Infections were probably transferred from adults via the environment to children. Infected children came from different socio-economic backgrounds. This condition should be considered in the differential diagnosis of nail diseases in children.

Onychomycosis in inflammatory bowel diseases

BACKGROUND

As far as we have sought for in Medline and PubMed, not one study until now has evaluated the prevalence of onychomycosis in patients with inflammatory bowel disease (IBD). As there are great evidence of immunological disturbances linked to IBD, a possible relationship of this nail infection in association with those diseases and the possible risk factors might be relevant in IBD patients.

METHODS

A case-control prospective study using combined direct smear and cultures for fungus was performed. Sociodemographics, clinical and laboratorial data were recorded at baseline and samples of suspected nails were collected from 141 IBD (61 men and 80 women) and from a group of 100 non-IBD subjects (41 men and 59 women). Direct smear and cultures were performed on each suspected case to exclude other onychodystrophies.

RESULTS

The incidence of onychomycosis in IBD patients was highly significant in comparison to non-IBD patients (14.9% vs. 6%, respectively, P < 0.05). The risk factors predisposing IBD patients to onychomycosis were older age (P = 0.02) and leucopoenia in those using azathioprine therapy (P = 0.04) beyond a trend to lymphopenia (P = 0.06). The dermatophytes predominated (76.2%) over yeasts (19%) and moulds (4.8%).

CONCLUSION

The prevalence of onychomycosis in IBD patients was expressively high (14.9%) in comparison with non-IBD patients. Considering the sociodemographic factors, any one but two were related to fungal onychomycosis incidence. Therefore, as far as we are concerned, IBD must be included in the high-risk underlying conditions for onychomycosis occurrence.

Onychomycosis: a 3-year clinicomycologic hospital-based study

BACKGROUND

Despite onychomycosis being an established entity, only a few studies are available from the Indian subcontinent. The authors investigated the comprehensive pattern of the condition.

AIM

To investigate the epidemiologic, clinical, and mycologic factors associated with onychomycosis in 50 patients using a prospective study design.

METHODS

Fifty patients with potassium hydroxide-positive tests were evaluated according to a predetermined protocal recording details of epidemiologic, clinical, and mycologic characteristics. The collected data were analyzed to determine the correlation of various parameters.

RESULTS

Distal and lateral subungual onychomycosis, total dystrophic onychomycosis, and superficial white onychomycosis variants of onychomycosis were identified, mostly in men 21-30 years of age (mean age, 34.5 years). Epidemiologic characteristics were instrumental to either initiate, perpetuate, or disseminate the disease process. Trichophyton rubrum and Trichophyton mentagrophytes were the main causative dermatophytes; yeasts and molds were less common.

CONCLUSIONS

Recognition of onychomycosis is less difficult providing the clinician is aware of the entity. Should the etiologic diagnosis be made, its eradication is desirable to surmount its implication in the society at large.

Onychomycosis is no longer a rare finding in children

Onychomycosis was considered uncommon in children. This survey was carried out to estimate the frequency of fungal nail infections in children and adolescents (0-18 years of age) attending our clinic in the last decade and gain more insight into the aetiology and clinics of this entity in the paediatric age group. This study is based on data obtained from 2320 children and adolescents suspected of superficial fungal infection. Onychomycosis was diagnosed in 99 cases, representing 19.8% of all mycologically confirmed superficial mycoses (500 cases) in our material. Fingernail onychomycosis was recognized in 52 (10.4%) cases; children under 3 years of age were predominantly involved. Candida albicans was the most common isolated pathogen. Toenail onychomycosis concerned 47 (9,4%) patients; the incidence increased steadily with increasing age. Trichophyton rubrum was the most common aetiological agent with respect to toenail infection followed by T. mentagrophytesvar. interdigitale and T. mentagrophytes var. granulosum. The majority of fungal nail infections were characterized clinically by distal and lateral subungual onychomycosis. The growing trend towards the frequency of toenail and fingernail onychomycosis in children and adolescents was found in the last decade in north Poland. The results of our study show that onychomycosis in prepubertal children is not exceptional and should be considered in differential diagnosis of nail plate disorders.

Proteolytic peptide patterns as indicators for fungal infections and nonfungal affections of human nails measured by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

The discrimination of onychomycoses from endogenous diseases showing macroscopically similar symptoms is difficult. Long-lasting but ineffective antifungal therapies using systemic medicaments with often severe adverse reactions may be the consequence. We introduce a novel mass spectrometric method for the discrimination of fungal infections and nonfungal affections. Horn samples from patients infected by Trichophyton rubrum, from patients with psoriasis affecting nails, and from healthy persons were investigated. Onychomycoses are basically associated with proteolytic attacks of the virulent fungi-secreting proteases partly hydrolyzing the horn material. Endogenous diseases lack these proteolytic activities, conserving intact structural proteins. Tryptical digestion of horn material produced cleavage peptides detectable by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Mass spectra of horn material infected by T. rubrum were clearly different from those originating from healthy test persons and from patients with psoriasis. Two methods were successfully applied to quantify the differences between groups of samples. One is based on the Euclidean match factor, and the other is based on the identification of specific peptide peaks occurring exclusively within one group of persons. The Euclidean match factor distributions and the occurrence of specific peptide peaks allowed a clear differentiation of T. rubrum infections from psoriasis patients and healthy test persons. No differences were found between healthy test persons and psoriasis patients. The method is rapid and does not require any cultivation.

Population-based epidemiologic study of tinea pedis in Israeli children

BACKGROUND

In recent years we have seen an increasing number of children in Israel with tinea pedis.

OBJECTIVE

To determine the prevalence of tinea pedis in 5- to 14-year-old schoolchildren in a comprehensive epidemiologic population-based study.

METHODS

A total of 1148 children, ages 5 to 14 years, from 7 schools with different socioeconomic backgrounds from the Jerusalem area were examined for the presence of tinea pedis. Scrapings from suspected lesions of fungal infection were sent to a mycologic laboratory for KOH microscopy and fungal identification. Information on the children's background and predisposing factors (regarding living conditions, hygiene, etc.) were provided by means of questionnaires filled out by each child.

RESULTS

Of the 1148 children examined, 29.6% exhibited erythema and scaling, but only 6.9% of these were mycologically positive for tinea pedis. was the main causative agent (68%) of tinea pedis. The prevalence of tinea pedis increased with age, hyperhidrosis and particularly repeated foot washing (a 3.2 higher rate in children who washed their feet twice a day those who did not wash daily).

CONCLUSION

The prevalence of tinea pedis in children has increased in recent decades in Israel and should be considered in the differential diagnosis of dermatologic diseases affecting the feet. Washing habits have a significant effect on tinea pedis in children.

The frequency of Candida species in onychomycosis

Mycological investigation of 108 nail specimens taken from a total of 41 patients examined over three years included direct microscopy and repeated cultures. A higher incidence of onychomycosis of the fingernails (75%) was observed in women while afflictions of the toenails (71%) prevailed in men. The highest prevalence of onychomycosis was found in patients between 50 and 70 years of age. Candida albicans was the dominant organism causing onychomycosis (prevalence rate 60.9%), followed by C. parapsilosis (19.6%), C. tropicalis (9.8), C. krusei (4.9), C. guilliermondii and C. zeylanoides (2.4% each).

Current Management of Onychomycosis and Dermatomycoses

Three newer oral antifungal agents, itraconazole, terbinafine and fluconazole, have revolutionized treatment of superficial mycoses. The tissue pharmacokinetics of itraconazole and terbinafine allow much shorter courses of therapy- with higher efficacy-in the treatment of onychomycosis, compared to other oral agents. Itraconazole pulse dosing and terbinafine daily dosing have shown comparable efficacy against dermatophyte onychomycosis; similar itraconazole regimens have been effective against nondermatophyte infections. Refractory clinical patterns of nail disease appear to be more responsive to oral antifungal therapy when combined with adjunctive therapy, such as debridement. These agents are effective against cutaneous dermatophytosis, with shorter treatment regimens. Tinea versicolor may be treated with a single-dose, intermittent, or daily regimen of an oral azole agent, depending on the drug selected. These newer oral antifungal agents have been proven effective against tinea capitis; effective regimens are shorter than those for griseofulvin. The safety profile of these newer agents has been very favorable.