Clinico - mycological study of dermatophytosis in Calicut

V Bindu¹ , K Pavithran²

¹ Department of Microbiology, Medical College, Calicut-673008, India
² Department of Dermatology and Venereology, Medical College, Calicut-673008, India

Correspondence Address:
K Pavithran
Department of Dermatology and Venereology, Medical College, Calicut-673008
India

Introduction

Dermatophytosis refers to superficial fungal infection of keratinised tissues caused by dermatophytes. Although common, the precise size of the problem defies measurement. The present study was undertaken to assess the clinicoepidemiological profile of dern-tatophytic infection, to identify the species of fungi and to compare the clinical diagnosis with KOH smear positivity and culture positivity.

Materials and Methods

The study population included 150 patients, diagnosed clinically as having dematophytosis randomly selected from the outpatient department of Dermatology and Venereology, Medical College Hospital, Calicut. A detailed history was taken from all patients. It included age, sex, socio-economic status, occupation, duration of disease, history of recurrence, habits and associated diseases. History of similar illness in family members and contact with animals or soil were also elicited. One hundred and fifty control subjects matched in terms of age, sex and socioeconomic status were also analysed. The patients were classified according to the sites of involvement. The skin scrapings were collected from the active edge of the lesions and roof of the vesicles if any. In tinea capitis infected and lustreless hairs were collected. In tinea unguium nail scrapings, clippings and sub-ungual debris were collected. Direct microscopy (in 10% KOH) and culture were done in each case. For primary isolation Sabouraud′s dextrose agar slopes with chloramphenicol and cycloheximide were used. Subculture was done in Sabouraud′s dextrose agar without antibiotics. Special tests were done when necessary viz; culture on cornmeal agar, blood agar and hair perforation test.

Results

Out of the 150 patients, the maximum were seen in the age group 11 -20 (23.3%). The youngest patient was a 13 day old boy (with age of onset at 9 days of age) and the oldest a 75 year old man. Male to female ratio was 2.06:1 Majority of the patients belonged to the middle - income group.

Tinea corporis (54.6%) was the commonest clinical type followed by tinea cruris (38.6%). Tinea capitis was the predominant dermatophytosis in children. Tinea axillaris and finea zoster were seen predominantly in females

and tinea faciei and tinea barbae in males. Tinea incognito was seen in 7.3% of patients. Mixed clinical types were also seen. Hence the total number of clinical types is higher than the total number of patients as shown in [Table - 1].

The overall positivity by culture was 45.3 and by direct microscopy was 64% See [Table - 2]

T rubrum was the predominant species isolated (66.2%) in all clinical types followed by Tmentagrophytes (25%), T tonsurans (5.9%) and E. floccosum ( 2.9%) as seen in [Table - 3].

Discussion

In the present study, maximum number of patients were seen in the second decade with males outnumbering females. Similar findings have been reported by other workers,[1],[2] although majority of studies have observed higher incidence in the third decade.[1],[2],[3],[4],[5],[6] The higher incidence in young males could be due to greater physical activity and increased sweating. The major clinical type was tinea corporis followed by tinea cruris. This is in agreement with majority of all cases of recurrent disease, extensive disease and tinea incognito. The second common isolate was Tmentagrophytes. This is in keeping with other studies from India.[1],[2],[4],[5],[7] Seventeen (11.3%) specimens were positive by culture alone 45 (30%) by direct microscopy alone, highlighting the improtance of both direct microscopy and culture in the definitive diagnosis of dermatophytosis. Specimens of nail and hair were frequently negative on direct microscopy. Positivity by culture and direct microscopy of nails was enhanced by combining the three methods of nail clipping, shaving or collection of sub ungual debris. This has been advocated by Hull and co-workers.[8]

History of contact with infected family members was seen in 16.6% and with non-family members in 2.6%. There was one case of conjugal transmission. Use of occlusive clothing and synthetic fabrics was seen in 64% of male patients and 80% of females compared to 22% and 32% in controls respectively. Tinea capitis was seen predominantly in male children. Frequent shaving of scalp and sharing of caps was found to be a contributory factor. There was no significant association with the use of hair oils and footwear in case of tinea capitis and tinea pedis respectively. Among the associated diseases, diabetes mellitus was seen in 10.6%, atopic diathesis in 10% and HIV-infection in 2%. Patients on immunosuppresants had extensive disease with mixed clinical types. Recurrence of disease noted in 32% of patients could be due to lack of local immunity or inadequate treatment ie, if treatment was stopped before all fungi are shed, then the disease will reestablish itself.[9] Uncommon clinical presentations included tinea labialis, kerion of upper lip, tinea of scrotum and penis, proximal subungual onychomycosis and kerion with dermatopathies. These have been reported and are by no means rare.[10],[11],[12]

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