Year : 2007 | Volume
: 52 | Issue : 1 | Page : 39--42
A five-year survey of onychomycosis in New Delhi, India: Epidemiological and laboratory aspects
Ravinder Kaur, Bineeta Kashyap, Preena Bhalla
Department of Microbiology, Maulana Azad Medical College, Bahadur Shah Zafar Marg, New Delhi - 110 002, India
Flat no. C-402, Plot no.- 03, Vimal CGHS Ltd, Sector - 12, New Delhi - 110 075
Context: The worldwide incidence of onychomycosis is increasing and it continues to spread and persist. Knowledge of the epidemiological and mycological characteristics is an important tool for control of this infection. Aims: This study seeks to improve knowledge of onychomycosis epidemiology and mycological features. Settings and Design: Over a period of five years (Jan 2000 - Dec 2005) samples from 400 patients with clinical suspected fungal nail infections, who attended dermatology out patient department at a tertiary care hospital, were obtained. Materials and Methods: 400 nail specimens of suspected onychomycosis were evaluated clinically, KOH examination and fungal culture was done. Results: Onychomycosis was present in 218 (54.5%) by culture and /or direct examination. Fingernails and toenails were infected in 65% and 32% respectively and remaining 3% had both. Conclusions: This study demonstrated that dermatophytes were main agents causing onychomycosis in our region, as well as the importance of performing direct examination and culture in diagnosis of onychomycosis.
|How to cite this article:|
Kaur R, Kashyap B, Bhalla P. A five-year survey of onychomycosis in New Delhi, India: Epidemiological and laboratory aspects.Indian J Dermatol 2007;52:39-42
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Kaur R, Kashyap B, Bhalla P. A five-year survey of onychomycosis in New Delhi, India: Epidemiological and laboratory aspects. Indian J Dermatol [serial online] 2007 [cited 2019 Dec 12 ];52:39-42
Available from: http://www.e-ijd.org/text.asp?2007/52/1/39/31923
Onychomycosis, a denomination used to describe nail infection usually caused by dermatophytes, yeast and nondermatophytic moulds, represents up to 20% of all nail disorders., Until the late 1990's, onychomycosis was a poorly discussed topic of medical science. Even in the financially more advanced Asian countries, onychomycosis has been highlighted only in the last decade.
The worldwide incidence of onychomycosis is increasing and a number of factors contribute to this rise. First, as the population ages, there are corresponding increases in chronic health problems, such as diabetes and poor peripheral circulation. Second, the number of persons who are immunocompromized because of infection with human immunodeficiency virus and the use of immunosuppressive therapies, cancer chemotherapy or antibiotics continue to expand. Third, avid sports participation is increasing the use of health clubs, communal swimming pools and occlusive footwear for exercise. In a small percentage of persons, onychomycosis may be caused by a genetic defect that causes alterations in immune function.
The prevalence rate of onychomycosis is determined by age, predisposing factor, social class, occupation, climate, living environment and frequency of travel. In spite of improved personal hygiene and living environment, onychomycosis continues to spread and persist. Unlike in western countries where it is the frequent cause of nail disorders, in south-east Asia the prevalence of onychomycosis is relatively low. This was partially confirmed by a large scale survey in Asia in the late 1990's in which the prevalence of onychomycosis was lower in tropical countries (3.8%) than in sub-tropical countries and countries in the temperate zone (18%).
Dermatophytes mainly Trichophyton rubrum and Trichophyton mentagrophyte var. interdigitale are responsible for nearly 90% of toenail onychomycosis and at least 50% of fingernail infections., Candida species, particularly C. albicans , prevail in fingernail infections. The incidence and clinical significance of other than dermatophytic fungi or moulds causing onychomycosis is unknown, because they may be colonizing organisms rather than pathogens. Though nondermatophytic moulds are rare, but a number of species, such as Fusarium spp.; Scytalidium spp. and Acremonium spp. have also been described as etiological agents of onychomycosis. In India, higher priorities in socioeconomic concerns and health issues for other diseases have resulted in low awareness of onychomycosis by physicians and the general public alike.
The epidemiology of onychomycosis has been well-studied in some countries, but few data are available in tropical countries. This study, therefore, seeks to improve knowledge of the epidemiology and the mycological features of onychomycosis.
Materials and Methods
Over a period of five years (Jan 2000 - Dec 2005) samples from 400 patients with clinical suspected fungal nail infections, who attended dermatology out patient department at a tertiary care hospital, were obtained.
The assessment of participants was conducted and consisted of an interview, clinical examination and collection of specimens for microbiological studies. All subjects completed a questionnaire that contained a demographic data, patient history, specific data related to risk factors for onychomycosis (age; gender; physical activities; occupation; predisposing diseases such as diabetes, cardiovascular disease, sharing of common facilities; and previous onychomycosis). The clinical appearance and location of onychomycosis (toenail/fingernail) were documented.
Specimen collection and processing
The specimens were obtained from clinically abnormal nails, by a vigorous scrapping of the nail bed, the underside of the nail plate and the hyponychyum, after cleaning the affected area with 80% ethanol. The samples of each patient were placed in separate sterile petridish and transported to the mycology laboratory. All specimens were analyzed by direct microscopy and culture. Scales scraped from the nails were analyzed for fungal elements, such as hyphae or blastoconidia, by direct microscopy examination, in potassium hydroxide (20%).
For fungal cultures, all samples were inoculated on each of two isolation media (1) Sabouraud dextrose agar (SDA, HiMedia Laboratories) (2) SDA with 5% chloramphenicol and cycloheximide in dublicate.
The culture tubes were incubated at 25°C and 37°C and examined daily for six weeks.
Growth in the culture medium was viewed as confirmation of dermatophytes as etiologic agents. In addition, the identification was confirmed by micromorphological aspects on slide culture and test on the positive urease. Confirmation of Candida species required direct or positive culture and observation of pseudomycelium under light microscopy with KOH.
The identification of non-dermatophytic fungi species was performed by following micro and macroscopic evaluations of the primary cultures and slide culture. When the light microscopy of a nail specimen showed filaments with only a non-dermatophytic growth in culture, a second nail specimen was examined again by light microscopy and culture to confirm nondermatophytic mould infection.
A total of 400 (210 male and 190 female) patients were examined. From 400 patients with clinical lesions in the nails, 218 (54.5%) had onychomycosis by culture and/or direct examination. Direct microscopic analysis was positive in 136 (34%) specimens. Clinical specimens from 38 patients were positive in microscopic examination, but had negative culture. In addition, fungal positive cultures were observed in 180 specimens, of which 98 and 82, respectively, were positive and negative in the direct examination [Table 1].
[Table 2] presents the distribution of cases by gender and by the age grouping. Onychomycosis was most prevalent in the 25 to 45 age group and the ratio of male to female onychomycosis patients was approximately 1.1. [Table 3] presents the distribution of cases positive by direct examination and/or culture by gender and by age grouping.
Fingernails were the most frequent anatomic site in 260 patients (65%) and toenail onychomycosis was confirmed in 128 patients (32%). In addition, 12 patients (3%) presented infections on fingernails and toenails simultaneously. The predominance of lesions in fingernails was higher in women (75%) than in men (25%). However, toenails were more affected in men (60%) than in women (40%).
[Table 4] presents the distribution of causative organism according to patient gender. The organism isolated most frequently in culture was dermatophytes (48.9%) followed by Aspergillus species (21.7%). In 2.7% of cultures, a mixture of dermatophyte and Candida or yeast or moulds was recovered. For yeast infections, C. albicans was found in 83.3% whereas the rest (16.7%) were due to other candida species. Of the 88 dermatophytes isolated, 35 could not be speciated and in the remaining 53 Trichophyton mentagrophytes was the most commonly involved, being responsible for 42 samples (79.2%). Other dermatophytic strains identified were Trichophyton rubrum, Epidermophyton floccosum, Microsporum gypseum and Trichophyton tonsurans . Regarding filamentous non-dermatophytic fungi, Aspergillus species (n = 39), Fusarium species (n = 2), Alternaria species (n = 2) and Penicillium species (n = 2) were the most frequently isolated. Occasionally, Bipolaris, Nigrospora, Curvularia and Scedosporium adiaspermum were isolated.
Onychomycosis is a chronic infection of the nails; nowadays considered a serious problem for public health, in view of it's high occurrence in the worldwide population. Although this disorder is not serious in terms of mortality or physical and/or psychological sequelae, it has significant clinical consequence given it's infectious nature, esthetic consequences, chronicity and therapeutic difficulties. The prevalence is probably higher than is currently thought, as the difficulty in clinical-mycological diagnosis, inappropriate collection of material for analysis as well as ineffective treatment make it hard to ascertain the true profile of such onychopathies.
The present study described, evaluated the prevalence and risk factors of onychomycosis in individuals representing different strata of population in New Delhi, India, in an attempt to define the epidemiology of this disorder in general population. In this study, the prevalence of onychomycosis was confirmed in 45% patients analyzed; these data exceeding those published in Madrid, Ontario, Northern Greece, Italy and Turkey respectively,,,,, but however lower than the results demonstrated by Lopes et al and Pontes et al of 56.6% and 66.5% respectively.
The average age of the population of positive patients analyzed in this study was 34.96 years. Within the female group, 59.6% of patients were between >25-45 years of age. Only 37.7% of men, however were affected between the ages of 25 and 45 years. The increased prevalence of onychomycosis in men compared to women could be the result of more traumas in the nails and the more common use of occlusive footwear. The increase in cases with age may be justified by repeated nail microtrauma, due to a more prolonged exposure to pathogenic fungi; as well as greater work activity and venous insufficiency. However, the prevalence decreased in patients over the age of 45 years unlike previous studies. Finally, corroborating epidemiological reports in other countries,,, our data indicate that onychomycosis is uncommon in children in our country. Despite previous reports of greater susceptibility of females to this infection,, our study demonstrated no such significant difference in the occurrence of onychomycosis on the basis of gender. Fingernails were affected more often than toenails in females, which can be explained by the work habits of such patients who, generally work performing domestic chores in some occupations. Thus hands remaining wet for most of the day. The increased prevalence of toenail infection in males could be the result of more traumas in the nails and the more common use of occlusive footwear.
Though yeasts have been quoted in the literature as being responsible for most cases of onychomycosis worldwide,, dermatophytes, especially Trichophyton mentagrophytes , were the etiological agents most widely found in our study population being responsible for 48.89% of cases evaluated.
The two conventional methods for fungi identification are direct microscopy under potassium hydroxide and fungal culture. The microscopic method is more sensitive for showing the presence of fungi, but the isolation of a specific genus and species of the pathogen requires fungal culture, which is often not very fruitful. Direct microscopy examination positivity in our case was 34%. This may be considered high when compared with the work of Kam et al . However it was lower than the positivity found in certain other studies. Culture was positive in 180 cases, including 82 (45.5%) with negative direct examination and 98 (54.4%) with positive direct examination. Hence, both tests are complementary to each other. The sensitivity of these diagnostic tests depends on the method of the sampling, preparation of sample, failure rate of microscopy and culture and the final interpretation of results. Nail clipping/scraping alone would have a lower yield than curette alone. It was suggested that a combination of curette and clipping would improve the yield. Moreover, histopathological examinations are more accurate tools to confirm the diagnosis of onychomycosis, but are seldom used.
Our study shows that onychomycosis is common in local patients. With the emergence of new effective systemic and topical antifungal therapies, study of the epidemiology and the extent of impact of this infection is important. In general, people should be more aware and physicians should be more clinically alert and should target their clinical suspicion to the higher risk groups to initiate prompt investigation and treatment. We hope that improvement in the current diagnostic methods or new development of more accurate and fast diagnostic methods will help us solve the existing diagnostic uncertainties.
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