Original Research

Incidence and Epidemiology of Onychomycosis in Patients Visiting a Tertiary Care Hospital in India

Cutis. 2015 January;95(1):E20-E25

References

1. Yenişehirli G, Bulut Y, Sezer E, et al. Onychomycosis infections in the Middle Black Sea Region, Turkey. Int J Dermatol. 2009;48:956-959.

2. Kouskoukis CE, Scher RK, Ackerman AB. What histologic finding distinguishes onychomycosis and psoriasis? Am J Dermatopathol. 1983;5:501-503.

3. Rippon JW. Medical mycology. In: Wonsiewicz M, ed. The Pathogenic Fungi and the Pathogenic Actinomycetes. 3rd ed. Philadelphia, PA: WB Saunders; 1988:169-275.

4. Greer DL. Evolving role of nondermatophytes in onychomycosis. Int J Dermatol. 1995;34:521-524.

5. Murray SC, Dawber RP. Onychomycosis of toenails: orthopaedic and podiatric considerations. Australas J Dermatol. 2002;43:105-112.

6. Achten G, Wanet-Rouard J. Onychomycoses in the laboratory. Mykosen Suppl. 1978;1:125-127.

7. Sobhanadri C, Rao DT, Babu KS. Clinical and mycological study of superficial fungal infections at Government General Hospital: guntur and their response to treatment with hamycin, dermostatin and dermamycin. Indian J Dermatol Venereol. 1970;36:209-214.

8. Jain S, Sehgal VN. Commentary: onychomycosis: an epidemio-etiologic perspective. Int J Dermatol. 2000;39:100-103.

9. Sehgal VN, Aggarwal AK, Srivastava G, et al. Onychomycosis: a 3 year clinicomycologic hospital-based study. Skinmed. 2007;6:11-17.

10. Elewski BE, Charif MA. Prevalence of onychomycosis in patients attending a dermatology clinic in northeastern Ohio for the other conditions. Arch Dermatol. 1997;133:1172-1173.

11. Scher RK. Onychomycosis is more than a cosmetic problem. Br J Dermatol. 1994;130(suppl 43):S15.

12. Godoy-Martinez PG, Nunes FG, Tomimori-Yamashita J, et al. Onychomycosis in São Paulo, Brazil [published online ahead of print May 8, 2009]. Mycopathologia. 2009;168:111-116.

13. Larone DH. Medically Important Fungi: A Guide to Identification. 4th ed. Washington, DC: American Society for Microbiology Press; 2002.

14. Sehgal VN, Srivastava G, Dogra S, et al. Onychomycosis: an Asian perspective. Skinmed. 2010;8:37-45.

15. Sanjiv A, Shalini M, Charoo H. Etiological agents of onychomycosis from a tertiary care hospital in Central Delhi, India. Indian J Fund Appl Life Science. 2011;1:11-14.

16. Gupta M, Sharma NL, Kanga AK, et al. Onychomycosis: clinic-mycologic study of 130 patients from Himachal Pradesh, India. Indian J Dermatol Venereol Leprol. 2007;73:389-392.

17. Eleweski BE. Diagnostic techniques for confirming onychomycosis. J Am Acad Dermatol. 1996;35(3, pt 2):S6-S9.

18. Das NK, Ghosh P, Das S, et al. A study on the etiological agent and clinico-mycological correlation of fingernail onychomycosis in eastern India. Indian J Dermatol. 2008;53:75-79.

19. Bassiri-Jahromi S, Khaksar AA. Nondermatophytic moulds as a causative agent of onychomycosis in Tehran. Indian J Dermatol. 2010;55:140-143.

20. Bokhari MA, Hussain I, Jahangir M, et al. Onychomycosis in Lahore, Pakistan. Int J Dermatol. 1999;38:591-595.

21. Jesudanam TM, Rao GR, Lakshmi DJ, et al. Onychomycosis: a significant medical problem. Indian J Dermatol Venereol Leprol. 2002;68:326-329.

22. Ahmad M, Gupta S, Gupte S. A clinico-mycological study of onychomycosis. EDOJ. 2010;6:1-9.

23. Vinod S, Grover S, Dash K, et al. A clinico-mycological evaluation of onychomycosis. Indian J Dermatol Venereol Leprol. 2000;66:238-240.

24. Veer P, Patwardhan NS, Damle AS. Study of onychomycosis: prevailing fungi and pattern of infection. Indian J Med Microbiol. 2007;25:53-56.

25. Garg A, Venkatesh V, Singh M, et al. Onychomycosis in central India: a clinicoetiologic correlation. Int J Dermatol. 2004;43:498-502.

26. Adhikari L, Das Gupta A, Pal R, et al. Clinico-etiologic correlates of onychomycosis in Sikkim. Indian J Pathol Microbiol. 2009;52:194-197.

Comment

The term onychomycosis is derived from onyx, the Greek word for nail, and mykes, the Greek word for fungus. Onychomycosis is a chronic mycotic infection of the fingernails and toenails that can have a serious impact on patients’ quality of life. The fungi known to cause onychomycosis vary among geographic areas, primarily due to differences in climate.¹⁴ The isolation rate of onychomycosis in our hospital-based study was 71.6%, which is in accordance with various studies in India and abroad, including 60% in Karnataka, India⁵; 82.3% in Sikkim, India⁶; and 86.9% in Turkey.¹ However, other studies have shown lower isolation rates of 39.5% in Central Delhi, India,¹⁵ and 37.6% in Himachal Pradesh, India.¹⁶ Some patients with onychomycosis may not seek medical attention, which may explain the difference in the prevalence of onychomycosis observed worldwide.¹⁷ The prevalence of onychomycosis by age also varies. In our study, participants older than 40 years showed the highest prevalence (47.8%), which is in accordance with other studies from India¹⁸ and abroad.^19,20 In contrast, some Indian studies^15,21,22 have reported a higher prevalence in younger adults (ie, 21–30 years), which may be attributed to greater self-consciousness about nail discoloration and disfigurement as well as increased physical activity and different shoe-wearing habits. A higher prevalence in older adults, as observed in our study as well some other studies,^19,21 may be due to poor peripheral circulation, diabetes mellitus, repeated nail trauma, longer exposure to pathogenic fungi, suboptimal immune function, inactivity, and poor hygiene.¹⁰

In our study, suspected onychomycosis was more common in males (58.2%) than in females (41.8%). These results are in accordance with many of the studies in the worldwide literature.^{1,10,11,15,16,23-25} A higher isolation rate in males worldwide may be due to common use of occlusive footwear, more exposure to outdoor conditions, and increased physical activity, leading to an increased likelihood of trauma. The importance of trauma to the nails as a predisposing factor for onychomycosis is well established.²⁴ In our study, the majority of males wore shoes regardless of occupation. Perspiration of the feet when wearing socks and/or shoes can generate a warm moist environment that promotes the growth of fungi and predisposes patients to onychomycosis. Similar observations have been reported by other investigators.^21,22,25,26

The incidence of onychomycosis was almost evenly distributed among farmers, housewives, and the miscellaneous group, whereas a high isolation rate was noted among students. Of 20 students included in our study, onychomycosis was confirmed in 16, which may be related to an increased use of synthetic sports shoes and socks that retain sweat as well as vigorous physical activity frequently resulting in nail injuries among this patient population.¹¹ Younger patients may be more conscious of their appearance and therefore may be more likely to seek treatment. Similar observations have been reported by other researchers.^15,21,22

In our study, dermatophytes were the most commonly found pathogens (58.3%), which is comparable to other studies.^15,18,22Trichophyton mentagrophytes was the most frequently isolated dermatophyte from cultures, which was in concordance with a study from Delhi.¹⁵ In some studies,^18,20,22Trichophyton rubrum has been reported as the most prevalent dermatophyte, but we identified Trichophyton rubrum in only 18 participants, which can be attributed to variations in epidemiology based on geographic region. Nondermatophyte molds were isolated in 12.5% of participants, with Aspergillus niger being the most common isolate found in 8 cases. Other isolated species were Alternaria alternata and Fusarium solani found in 2 cases each. Aspergillus niger has been reported in worldwide studies as an important cause of onychomycosis.^{15,18,19,21,22}

In 28 cases (29.2%) involving Candida species, Candida albicans, Candida parapsilosis, and Candida tropicalis were the most common pathogens, respectively, which is in accordance with many studies.^15,20-22,25 In 28 cases of CO, females (n=16) were affected more than males (n=12). All of the females were housewives and C albicans was predominantly isolated from the fingernails. Household responsibilities involving kitchen work (eg, cutting and peeling vegetables, washing utensils, cleaning the house/laundry) may chronically expose housewives to moist environments and make them more prone to injury, thus facilitating easy entry of fungal agents.

Distal lateral subungual onychomycosis was the most prevalent clinical type found (n=66), which is comparable to other reports.^20,22,25 Proximal subungual onychomycosis was the second most common type; however, a greater incidence has been reported by some researchers,^23,24 while others have reported a lower incidence.^20,21 Candidial onychomycosis and WSO were not common in our study, and PSO was not associated with any immunodeficiency disease, as reported by other researchers.^15,20

Of 134 suspected cases of onychomycosis, 71.6% were confirmed by both direct microscopy and fungal culture, but only 56.7% were confirmed by direct microscopy alone. If we had relied on microscopy with potassium hydroxide only, we would have missed 23.9% of cases. Therefore, nail scrapings should always be subjected to fungal culture as well as direct microscopy, as both are necessary for accurate diagnosis and treatment of onychomycosis. If onychomycosis is not successfully treated, it can act as a reservoir of fungal infection affecting other parts of the body with the potential to pass infection on to others.

Conclusion

Clinical examination alone is not sufficient for diagnosing onychomycosis^14,18,20; in many cases of suspected onychomycosis with nail changes, mycologic examination does not confirm fungal infection. In our study, only 71.6% of participants with nail changes proved to be of fungal etiology. Other researchers from different geographic locations have reported similar results with lower incidence (eg, 39.5%,¹⁵ 37.6%,¹⁶ 51.7%,¹⁸ 45.3%²¹) of fungal etiology in such cases. Therefore, both clinical and mycologic examinations are important for establishing the diagnosis and selecting the most suitable antifungal agent, which is possible only if the underlying pathogen is correctly identified.