Clinico – mycological profiles of dermatophytoses in a tertiary care rural hospital

Dermatophytosis is seen all over the world, both urban and rural areas. 5 In India, like other tropical and sub-tropical countries, cases of dermatophytoses are significantly high due to favorable climatic conditions. Prevalence of infection with different species of dermatophytes varies with geographical locations and conditions. Most of the patients, acquiring dermatophytic infection are diagnosed and treated by clinicians without any laboratory


Introduction
The dermatophytes are a group of fungi which have the capacity to invade keratin layer of skin, hair, nail, fur etc. of humans and lower animals. 1 The first recorded dermatophytic infection was attributed to Aulus Cornelius Celsus who in a book "De Re Medica" described "Kerion" of the scalp as early as 300 A.D. 2 Sabouraud classified dermatophytes into four genera-Achorion (A), Trichophyton (T), Epidermophyton (E) and Microsporum (M). 3 The literal meaning of 'dermatophyte' is 'skin plant'. This can attack various anatomical sites. 4 Dermatophytosis is seen all over the world, both urban and rural areas. 5 In India, like other tropical and sub-tropical countries, cases of dermatophytoses are significantly high due to favorable climatic conditions.
Prevalence of infection with different species of dermatophytes varies with geographical locations and conditions. Most of the patients, acquiring dermatophytic infection are diagnosed and treated by clinicians without any laboratory confirmation. 6 The present study was undertaken with the aim to determine the prevalence of dermatophytoses in a tertiary care hospital of Maharashtra, serving a rural population and to find out common clinical types of dermatophytes.

Material & Methods
The study population consisted of patients attending the dermatology department at a tertiary care rural hospital.
The study was carried out in Microbiology department. Only cases with a strong suspicion of cutaneous mycotic infection were selected from patients attending Skin & Venereal department of the same hospital. Microbiological investigations : A total of 150 patients were included in this study over a period of one year.
Scrapings were taken from the periphery of the lesions after proper sterilization of the surface with 70% alcohol. Samples were collected in sterile paper envelopes or in sterile Petri dishes. Affected hairs were epilated with forceps and nails were cut or clipped. Powdery debris under the nail was also collected. Wood's lamp examination was done in suspected cases of Tinea capitis.
Direct examination was done by Potassium Hydroxide (KOH) preparation and Gram staining. Direct microscopy of skin, hair and nail clippings were done using 10% or 20% KOH plus Dimethyl sulfoxide (DMSO).
Gram staining was done in suspected cases of Candida infection. Culture was done on plain Saboraud's dextrose agar and Saboraud's dextrose agar with cycloheximide. Tubes and plates were incubated at 37˚C and room temperature. For primary isolation of fungus from clinical specimens, Dermatophyte Test Medium was also used. The sterile culture tubes and plates were discarded after four weeks.
The species identification of dermatophytes isolated on culture was done by observing gross morphology, rate of growth, surface texture and pigment production, and microscopically by lacto-phenol cotton blue mounts. Fungal hyphae, size, shape and arrangement of micro and macro conidia and presence of other special structures like racquet hyphae, spiral hyphae etc. were observed. Slide culture was also done to appreciate better morphology. T rubrum was differentiated from T mentagrophytes by urease test, hair perforation test and pigment production. 1,3,7,8,9 Candida albicans (C albicans) was identified by Gram staining, germ tube test and chlamydospore formation test on cornmeal agar. Tinea versicolor were diagnose on the basis of microscopy only because causative agent of Tinea versicolor i.e. Malassezia furfur was difficult to grow in the laboratory. 8

Results
A total of 150 clinically suspected cases of cutaneous mycotic infections were examined for the presence of dermatophytes. In the present study, we observed that dermatophyte infections were more common in the age group of 21-30 years (37.33%), except in Tinea capitis infection, which was among the patients of age group 1-10 years. (Table-1   The clinical types prevalent in this area were Tinea corporis (42%), Tinea cruris (28%), Tinea unguinum (4.66%), Tinea capitis (4%), Tinea mannum, Tinea pedis and Tinea barbae (3.33% each). Incidence of mixed infection was 6.67%. ( Table -1) Out of the 150 cases, 81(54%) were both KOH and culture positive and 41(27.33%) were only culture positive. In KOH positive cases, the fungal element appeared as thin, septate, branching filament.

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In 4 (4.39%) cases, we isolated C albicans. All these 4 cases were clinically diagnosed as Tinea unguinum. T rubrum was mainly isolated from Tinea corporis and Tinea cruris. All E floccosum isolates were obtained from Tinea cruris cases.

Discussion
Dermatophytosis is the commonest group of superficial fungal infection seen in the tropics. All races are usually affected and the clinical varieties and prevalence appear to depend mainly on environmental factors. 7 In our study, male female ratio of infection was approximately 4:1. The reason behind high incidence in male may be due to maceration effect of hyperhidrosis in comparison to females. 10 The males are usually more exposed to infection during their outdoor occupation and females, especially of rural background, rarely seek medical advice for a fungal infection. In case of Tinea pedis, higher incidence in male is seen probably due to their use of heavy, closed footwear while females mostly use open, ventilated footwear. 5,11,12 Infection was commonest in the age group of 21-30 years (37.33%) 13 . Similar finding was observed by other workers. 13 Exception to this is Tinea capitis infection, which was common among the patients of age group 1-10 years. (Table -1).Grover et al (2010) also reported similar type of findings. 14 Tinea capitis rarely occur in normal healthy adults. This may be due to increased fungistatic triglyceride content of sebum in adults. 3 Some authors associated low incidence of Tinea capitis in India with use of hair oil . 15 The most prevalent clinical type was Tinea corporis (42%) followed by Tinea cruris (28%). The least incidence was of Tinea mannum, Tinea pedis and Tinea barbae i.e. 3.3%. The highest incidence of Tinea corporis among cases of dermatophytoses was also noted by several researchers. 12,13 However some workers found Tinea cruris as the commonest clinical type . 16,17 IJBAR (2013) 04 (01) www.ssjournals.com The main reason behind the high prevalence of above mentioned groups i.e., Tinea corporis and Tinea cruris is the severe itching which induces the patient to seek medical advice. The patients with non-inflammatory Tinea versicolor usually seek medical advice for cosmetic reasons and due to fear of early leukoderma. 18 We got 7 (4.66%) cases of Tinea versicolor. T rubrum (33.33%) was by far the commonest etiological agent in cases seen in this part of the country followed by T mentagrophytes (21.33%). The incidence of E floccosum infection was only 3.29%. This may be due to climatic differences from other regions, this part of Maharashtra being less humid throughout the year. We had 2 cases of M gypseum (2.19%) infection from the same family. The latter organism, although extremely common in the soil, is a rare human pathogen . 18 We isolated 4 C albicans (4.39%) from cases of Tinea unguinum. All of them were females. This most likely reflects the greater burden of wet work performed by the females . 17 Direct detection of dermatophyte DNA (deoxyribonucleic acid) in clinical specimens takes less time and is more sensitive 19 but due to cost constraint, may not be possible in a rural set up. There is evidence that predominance of species of dermatophytes not only differs from region to region but may change with the passage of time 20 Dermatophytosis is not a reportable disease. Because of its contagious nature, an early diagnosis is needed to control transmission of infection. Some of the species of dermatophytes show slower response to azole derivatives. So it is important to find out the etiological agents up to species level. 21

Conclusion
Species identification by microscopy and culture are easy to perform, cost effective and reproducible method and should be done in all suspected cases of Dermatophytosis. Physical and psychosocial problems of Dermatophytosis are not to be underestimated.