Clinico Mycological study of Onychomycosis

Sudha, A (2010) Clinico Mycological study of Onychomycosis. Masters thesis, Stanley Medical College, Chennai.


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INTRODUCTION : Onychomycosis is a fungal infection of the nail bed, matrix (or) plate caused by dermatophytes, nondermatophyte moulds and yeasts. It accounts for 50% of all nail diseases and 30% of mycotic cutaneous infections. In developing countries, higher priorities to health issues for other diseases have resulted in low awareness of onychomycosis by physician and general public alike. Onychomycosis is all too often regarded as merely a cosmetic problem of relatively minor importance, to seek treatment. This belief may have been supported by the adverse effects and long courses of treatment associated with some earlier antifungal agents. But now safer, effective, short course, systemic treatments are available. Although onychomycosis is not life threatening, its high incidence and prevalence and associated morbidity makes it an important public health problem, and it is the major cause of nail disease. Hence an attempt is made to study the prevalence, causative organism and therapeutic response to topical and systemic antifungal agents in onychomycosis. AIMS AND OBJECTIVES : 1. Age and sex distribution of the patients with onychomycosis. 2. Clinical types of onychomycosis. 3. Isolation of causative organisms. 4. Precipitating factors. 5. Associated dermatological conditions. 6. Associated systemic diseases. 7. Therapeutic trial with systemic terbinafine alone, topical amorolfine alone and both together. MATERIALS AND METHODS : This randomized single-blind longitudinal clinical comparative study was undertaken during the period of Aug 2008 to July 2009. 108 patients presenting to our department out patient clinic with clinical features of finger nail or toe nail onychomycosis (eg. Discolouration, thickening, crumbling or destruction of nail plate, subungual debris and onycholysis) were subjected to detailed history, clinical examination and investigations like potassium hydroxide (KOH) mount and culture from nail clippings/ scrappings. 89 patients were either KOH, culture or both positive. Among these who had received systemic/ topical antifungal therapy in the last six months, pregnant, lactating, those with elevated hepatic enzymes, not willing for study were excluded from the drug trial. Only 60 patients were randomly selected for study and divided into three groups (A, B, C). Group A received oral terbinafine alone 250mg daily for 6/12 wks, Group B received topical amorolfine alone once weekly for 6 months, Group C received oral terbinafine daily for 6/12wks plus topical amorolfine once weekly for 6 months. The patients were evaluated at 6weeks, 12 weeks and 24 weeks. During these visits they were assessed for the growth of the normal and healthy nail plate and were inquired for any adverse effects of the drugs. In addition, microscopic examination and culture of nail material were done at 12, 24 weeks. Direct microscopy was done after overnight incubation of the nail specimen in 40% KOH for the presence of fungal mycelia and spores. All the nail specimens were cultured on sabouraud dextrose agar (SDA) with chloramphenicol and with or without cycloheximide. The cultures were observed twice a week for a period of 4 weeks and were discarded if there was no growth at the end of 4 weeks. The culture tube was examined for colour of the colony (on the surface and reverse), texture, and rate of growth. In the presence of growth, a loopful of growth was taken and examined using a lactophenol cotton blue mount. Slide culture was also done if required and was examined for characteristic morphology. The criteria used for the diagnosis of dermatophytes were, - If a dermatophyte was identified on KOH mount and/or isolated on culture, it was pathogenic. The criteria used for the diagnosis of Nondermatophytic moulds [NDM] were, - demonstration of fungal filaments on KOH mount and - Isolation of NDM in culture. Isolation of NDM on three occasions was considered as pathogenic. RESULTS : Out of 89 patients, 37 were male patients (41.5%) & 52 were female patients (58.5%) giving a sex ratio of 1:1.4. The most commonly infected was the 51-60 yrs age group[21 patients] followed by 31-40 yrs age group[19 patients] 41-50 yrs (17 patients), 21-30 yrs (15 patients), <20yrs (10 patients) and above 60 yrs (7 patients). Infection was less common in the age group below 10 years, whereas infection was high above 50 years. Youngest age in this study was 3 years. Oldest age was 70. CONCLUSION : Females are more commonly affected than males. Common age group is between 31-60 yrs. Trauma, Diabetes were found to be the precipitating factor. Finger nail involvement is found more than toe nail involvement. Distal and lateral subungual onychomycosis is the commonest type. Nondermatophyte moulds are commonly isolated than dermatophytes, yeasts. No specific systemic disease association is noted in this study. Therapeutic trial concludes that terbinafine monotherapy is as good as combination therapy. The clinicoetiological correlation reveals that a single pathogen may give rise to various clinical types. The recognition of the changing prevalence of etiological agents will aid in the therapeutic approach and the potential implementation of the control measures. The efficacy, short duration, lesser side effects, cost effectiveness of the drug (particularly Terbinafine) gives a positive approach in the treatment of onychomycosis.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Onychomycosis ; Clinico Mycological Study.
Subjects: MEDICAL > Dermatology Venereology and Leprosy
Depositing User: Subramani R
Date Deposited: 02 Mar 2018 02:43
Last Modified: 02 Mar 2018 02:43

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