Australas J. Dermatol 1992; 33: 159-163

DERMATOPHYTE AND NON-DERMATOPHYTE IN SINGAPORE

JOYCE TENG-EE LIM, HOCK CHENG CHUA AND CHEE LEOK GOH Singapore

SUMMARY Onychomycosis is caused by dermatophytes, moulds and . It is important to identify the non-dermatophyte moulds as they are resistant to the usual anti-fungals. A prospective study was undertaken in the National Skin Centre, Singapore to study the pattern of dermatophyte and non-dermatophyte onychomycosis. 53 male and 47 female patients seen between June 1990 and June 1991 were entered into the study. Direct microscopy was done and the clippings were cultured. Toe and finger nails were equally infected. Dermatophytes were isolated from 21 patients namely, T. rubrum (12/21), T. interdigitale (5/21), T. mentagrophytes (3/21) and T. violaceum (1/21). Candida onychomycosis occurred in 39 patients and was caused by C. albicans (38/39) and C. parapsilosis (1/39). 37/39 patients had associated . 5 types of moulds were isolated from 12 patients, namely species (6/12), species (3/12), S. brevicaulis (1/12), Aureobasilium species (1/12) and Penicillium species (1/12). Although the clinical pattern and microscopy may predict the type of organisms, in practice this is difficult. Only cultures were confirmatory. 28% (28/100) had negative cultures despite a positive microscopy, and moulds (12/100) grown might be contaminants rather than pathogens.

Key words: Moulds, yeasts, fungi, tinea, onychomycosis, dermatophyte, non-dermatophyte

INTRODUCTION METHODS AND MATERIALS Onychomycosis, a common nail disorder, is 100 consecutive patients, seen in our centre caused by dermatophytes, non-dermatophyte between June 1990 and June 1991, with a new moulds, or yeasts. Mixed infections have been clinical diagnosis of onychomycosis were included reported but are rare. The incidence of in the study. Diagnosis was confirmed by the onychomycosis due to dermatophyte or non- presence of fungal elements (mycelium, dermatophyte varies from place to place. The arthrospores and ) on direct microscopy of routine incorporation of cycloheximide in nail and subungal scrapings dissolved with 30% mycological media which inhibits the growth of potassium hydroxide. Only patients with a moulds may explain the low incidence in some positive microscopy were included in the study. reports. The incidence of these organisms causing Patients with skin disorders causing onychodys- onychomycosis in Singapore is unknown. We trophy or patients with chronic mucocutaneous carried out a prospective study to determine the were excluded from the study. The pattern of dermatophyte and non-dermatophyte patients' demographic data were recorded. The onychomycosis in patients attending the National duration, symptoms, characteristics and location Skin Centre in Singapore. of the onychomycosis were recorded. Scrapings from nails and nail beds were put in 30% potassium hydroxide for microscopy. Nail Joyce Teng-Ee Lim, MBBS (Malaysia), MRCP (Ire), FAMS. Senior Registrar, National Skin Centre, Singapore. clippings from all patients were dissolved in 30% Hock Chengh Chua, MBBS (Australia). Visiting Fellow. potassium hydroxide overnight and inoculated Currently Dermatology Trainee, Perth, Australia. into two types of media. Where more than one Chee Leok Goh, FAMS, MMed (Singapore), MRCP (UK). site was involved, the specimens were pooled. Medical Director and Clinical Professor, National Skin Mycobiotic agar (Difco Laboratories, Michigan, Centre, Singapore. Address for correspondence: Dr J. Lim, National Skin Centre, USA) was used for growing dermatophytes and 1 Mandalay Rd, Singapore, 1130. it contained Bacto-Soytone (lOg/1), Bacto-

159 JOYCE TENG-EE LIM, HOCK CHENG CHUA AND CHEE LEOK GOH

Dextrose (lOg/1), Bacto-Agar (15g/l), Actidione (0.5g/l) and Chloromycetin (0.05g/l). Modified (Difco Laboratories, Michigan) containing Bacto-Neopeptone (lOg/1), Bacto- Dextrose (20g/l), Bacto-Agar (20g/l) and Chloromycetin (0.05g/l) was used to culture non- dermatophytes. All cultures were incubated at room temperature (ZS^C to SO^C). The cultures

were examined on the 3rd, 6th, 9th and 12th day. Dermatophyte Morphology of fungi colonies and growth Negative characteristics were recorded. Cultures were again NUMBER OF PATIENTS examined at six weeks for slow-growers. No I Chinese [sEJ Malay I . I Indian growth at six weeks was considered negative. Positive cultures were confirmed and identified FIGURE 2—Culture Results of Onychomycosis according to by wet mounts and/or slide cultures when race. necessary. Candida species isolated were identi- fied using germ tube production, morphology on cornmeal media and mycotube identification system ("Mycotube" Roche). Thex^ test was used for statistical analysis. P values ^^0.05 were considered significant.

RESULTS 100 patients (53 male and 47 female) were included in the study. Their ages ranged from 3 years to 79 years, with a mean age of 45.2 years. The majority were adults from the third to the fifth decade. Figure 1 shows the age distribution of the patients and the type of organisms cultured. There were 68% Chinese, 21% Indians, 8% Malays and 3% comprising the other minority racial group. The racial composition of FIGURE 3—Type of Organism Causing Onychomycosis the general dermatological patients attending the according to sex Centre during this time was 76.4% Chinese, 9.5% Indians, 8.6% Malays and 5.6% others. There 2 shows the racial distribution and the organisms were no significant differences in the incidence cultured. Onychomycosis was seen in all the of infection in the different races, when compared occupation groups. However, 66% of the female to the general dermatological population. Figure patients were housewives doing wet work. 50/100 patients had onychomycosis for more than two years, 5/100 patients for less than a NUMBER OF PATIENTS month and the remaining (45/100) had the infection from between 1 to 24 months. 66/100 patients presented because of deformity or dyschromia of their nails. The others had pain (16/100), itch (13/100) or both (5/100). The total number of nails involved varied from less than 5 nails (57/100 patients) to more than 15 nails (10/100 patients). Onychomycosis involved the 0-9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 AGE GROUP finger-nails in 43/100 patients, the toe-nails in 35/100 patients and both finger and toe nails in 22/100 patients. FIGURE 1—Culture Results of Onychomycosis according to 28% (28/100) had a negative culture despite a age group positive microscopy. Table 1 shows the type of 160 DERMATOPHYTE AND NON-DERMATOPHYTE ONYCHOMYCOSIS IN SINGAPORE

TABLE l DISCUSSION Type of Organism Cultured by Site Onychomycosis in children is uncommon', with Finger Nails Toe Nails Total a prevalence rate of from 0.2% to 0.6% in the general population.^' When it does occur the Dermatophytes parents may act as the source of infection.^ The T. interdigitale 2 4 6 T. rubrum 8 9 17 usual organism isolated is T. rubrum. However, T. mentagrophyte — 3 3 one of our children had Candida onychomycosis. T, violaceum 1 — 1 This is uncommon in children unless it occurs Moulds secondary to an underlying nail or systemic S. brevicaulis — 1 1 pathology. Our patient had no such predisposing Aureobasidium — 1 1 factors but her mother had a similar condition Fusarium 2 5 7 suggesting that she could have been the source Aspergillus — 3 3 of infection. 95% of our patients were adults con- Penicillium — 1 1 curring with reports that onychomycosis is an Candida adult disorder.^' C. albicans 34 11 45 Onychomycosis is a chronic disorder and is C. parapsilosis 1 1 2 often resistent to treatment. Our study concurred with this. Patients are usually asymptomatic and do not seek treatment, another reason for the organisms cultured and the site. Dermatophytes chronicity of the infection. The presenting caused infection in 21/100 of the patients (Figure complaint in our study was cosmetic, noted in a 3), and only four species were cultured. These previous report.' were T. rubrum (12/21), T. interdigitale (5/21), T Dermatophyte onychomycosis usually starts in mentagrophytes (3/21) and T. violaceum (1/21). the toe-nails, especially the big toes.*^ Candida Those patients who had T. mentagrophytes onychomycois, in contrast, affects the finger-nails infection had no animal contact and no zoophilic early. In our findings, the initial site of infection infection on another part of the body. As the was not predictive of the causative organisms, as zoophilic variety is unusual in toe nails and these Candida had been isolated from toe-nails alone patients had no sign of zoophilic infection else- and dermatophytes from finger-nails alone. where, we assumed that they might be an Zaias^ divided onychomycosis into four clinical anthropophilic variety, the variety not identified. types namely, distal subungual onychomycosis 12/21 of these patients had associated (DSO), proximal subungal onychomycosis (PSO), dermatophyte infection elsewhere and the same superficial white onychomycosis (SWO) and species of clermatophyte were cultured from the Candida onychomycosis. The majority of our skin sites. 39/100 had Candida onychomycosis patients (30/100) had total subungal onycho- and these were caused by 2 species namely, C. and it was difficult to determine the albicans (38/39) and C parapsilosis (1/39). All clinical type. One patient had SWO of the toe- but 2 patients with Candida onychomycosis had nail caused by T. interdigitale, which was also associated paronychia. 12/100 had a positive reported to be the commonest dermatophyte culture for non-dermatophyte mould. The causing this infection."^ PSO, the rarest clinical moulds isolated were namely, Fusarium species type, was present in 2 of our patients. Both (6/12), Aspergillus species (3/12), S. brevicaulis affected the toe-nails and was caused by T. (1/12), Aureobasidium species (1/12) and rubrum. However, morphology was not a Penicillium species (1/12). predictive feature to differentiate dermatophyte Dermatophyte onychomycosis affected more from non-dermatophyte onychomycosis in our male patients whereas Candida onychomycosis patients, except for the presence of paronychia were common in female patients (Figure 3). which tended to suggest a diagnosis of Candida Mould onychomycosis affected both male and onychomycosis. female patients equally. However, moulds were The positive culture rate in onychomycosis, not recovered from the two extremes of ages even in the presence of positive direct microscopy, (Figure 1). There was also no difference in the varies from 30 to 50%.' * Therefore, methods type of organisms recovered from the different like suction drill sampling*' have been races (Figure 2). suggested to increase the yield. Other authors

161 JOYCE TENG-EE LIM, HOCK CHENG CHUA AND CHEE LEOK GOH

have used scanning electron microscopy'" to help Aspergillus spp. and Penicillium were isolated in make the diagnosis. Dermatophyte onycho- our study. It was felt that Aureobasidium and mycosis is commonly due to T. rubrum, T. menta- Penicillum were contaminants as the cultures were grophytes and E. floccosum.'" '^ Four types not reproducible. The other moulds were namely T. rubrum, T. interdigitale, T. menta- considered to be significant using the criteria grophytes and T. violaceum were isolated in our suggested by English;^ that is, positive microscopy study. There was no infection by E. floccosum as and repeated cultures without isolation of this was not a common cause of tinea pedis in dermatophytes. Singapore. The commonest dermatophyte recov- Six of our patients had Fusarium onycho- ered was T. rubrum, which is also the commonest mycosis. Although normally known as a skin dermatophyte reported previously."'^ '^ Derma- contaminant, Fusarium had been reported to tophyte onychomycosis occurred in all age groups cause fungal keratitis," superficial onychomyco- and was more common in male than female sis" and even osteomyelitis.^' The commonest patients, as is reported els where.""' species reported to cause disease was F. Candida onychomycosis occurs in three oxysporum. We were unfortunately unable to patterns,"* namely (a) associated with chronic identify the species. mucocutaneous candidiasis, (b) associated with This study showed that onychomycosis in paronychia and lateral onycholysis and (c) Singapore is caused by either dermatophytes associated with primary distal and lateral (21%) or yeasts (39%). Moulds (12%) are an onycholysis. The majority of our patients (37/39) uncommon cause. Moulds are resistant to the had associated paronychia suggesting that the nail commonly used anti-fungal agents and hence infection was secondary to Candida paronychia. their identification is important in preventing However, in two patients paronychia was absent such medications from being prescribed. Methods and there was also subungual hyperkeratosis used to distinguish them include the clinical suggesting that the onychomycosis was a primary pattern and site of infection. For example PSO event. It is important to differentiate between has not been documented to be caused by mould these two types as it has been reported that the and yeasts. Microscopy may help as some moulds latter pattern responds poorly to topical have a fronded appearance. Their hyphae are agents.""' The organisms responsible for the hyaline, have a more variable width, swollen or onychomycosis were C. albicans and C. distorted^" and in some may be pigmented or parapsilosis. Our findings concurred with appear double-contoured.^' Although available, previous reports that Candida onychomycosis is these measures are usually not helpful in the more common in females and affects finger nails chnical situation. Theref'ore, culture media more."" Those with toe-nail infections had without cycloheximide is used if non- concomitant finger-nail infections, which prob- dermatophytes are suspected. The significance of ably explained the relatively high numbers of toe- any non-dermatophyte isolated must be nail Candida onychomycosis in our study. The confirmed by isolating the organisms in 5 out of infection was uncommon in the extremes of age 20 inocula without concomitant isolation of any where wet-work and hence paronychia was less dermatophytes (as suggested by Enghsh'O. of a problem. Onychomycosis due to moulds has been ACKNOWLEDGEMENT reported to occur on dystrophic nails and hence We would like to thank Mr Kamarudin bin Ali to have a higher incidence in older patients.'^ '^ and Mr Koh Mong Teck for their technical Our study showed that it was common in the assistance. second to the fifth decade, with no cases in the extremes of age. The toe nails were affected in all REFERENCES cases, concurring with previous reports.'^'' In ' Roberts SOB, Mackenzie DWR. Mycology. In: Rook AJ, two patients their finger nails were infected in Wilkinson DS, Ebling FJG. eds. Textbook of Dermatology. addition to their toe-nails. Moulds reported to London. Blackwell Scientific Publications. 4th Edition cause onychomycosis include Aspergillus 1986; 923-925. ^ Philpot CM, Shuttleworth D. Dermatophyte onychomycosis species,"" Fusarium species,"" Hendersonula in children. Clin Exp Dermatol 1989; 14: 203-205. toruloidea,^" S. brevicaulis^' and others.""" S. ' Findlay GH, Vismar HF, Sophianos T. Spectrum of brevicaulis, Aureobasidium, Fusarium spp.. paediatric dermatology. Br J Dermatol 1974; 91: 379-387. 162 DERMATOPHYTE AND NON-DERMATOPHYTE ONYCHOMYCOSIS IN SINGAPORE

Goslan JB, Kobayashi GS, Mycologic Infections. In: Watanabe S, Seki Y, Shimozuma M. Tkkizawa K. Nail Fitzpatrick TB, Eisen AZ, Wolff K. eds. Dermatology in Candidiasis. J Dermatol 1983; 110: 189-203. General Medicine. New York. McGraw-Hill. 3rd Edition Bereston ES, Waring WS. Aspergillus infections of the nails. 1987; 2223-2226. Arch Dermatol Syph 1946; 54: 552-557. Zaias N. Onychomycosis - a review. Arch Dermatol 1972; DiSalvo AF, Fickling AM. A case of non-dermatophyte 104: 263-274. toe onychomycosis caused by Fusarium oxysporum. Arch Baden HP. Diseases of the and nails. Year Book Dermatol 1980; 116: 699-700. Medical Publishers. 1987; 27-30. Veglia KS, Marks VJ. Fusarium as a pathogen. A case Gentles JC. Laboratory investigations of dermatophyte report of Fusarium species and review of the literature. J infection in nails. Sabouraudia 1971; 9: 149-52. Am Acad Dermatol 1987; 16: 260-263. English MP, Lewis L. Ringworm in the South-West of Rush-Munro FM, Black H, Dingley JM. Onychomycosis England, 1960-1970, with special reference to caused by Fusarium oxysporum. Aust J Dermatol 1971; onychomycosis. Br J Dermatol 1974; 90: 67-75. 12: 18-21. Zaias N, Obertel I, Elliott DF. Fungi in toe nails. J Invest Campbell CK. Studies on Hendersonula toruloidea isolated Dermatol 1969; 53: 140-142. from and nail. Sabouraudia 1974; 12: 150-156. Sungnack L, Dongsik B. Subtle clues to diagnosis by Campbell CK, Mulder JL. Scytalidium hyalinum infection scanning electron microscopy: Hyphae on the ventral in skin and nail. Sabouraudia 1977; 15: 161-166. nailplate as a clue to onychomycosis. Am JDermatopath Zapates R, Arrechea A. Mycotic keratitis by Fusarium. 1987; 9: 445-446. Ophthalmologica 1975; 170: 1-12. Ramesh V, Reddy BSN, Singh R. Onychomycosis. Int J Bourguignon R, Walsh A, Flynn J. Fusarium species Dermatol 1983; 22: 148-152. osteomyelitis: a case report. / Bone Joint Surg (Am) 1976; English MP, Atkinson R. Onychomycosis in elderly 58: 722-723. chiropody patients. Br J Dermatol 1974; 91: 67-72. Peiris S, Moore MK, Marten RH. Scytalidium hyalinum English MP. Nails and fungi. Br J Dermatol 1976; 94: infection of skin and nails. Br J Dermatol 1978; 100: 697-701. 579-584. Hay RJ, Baran R, Moore MR, Wilkinson JD. Candida Moore MK. Hendersonula toruloidea and Scytalidium onychomycosis - an evaluation of the role of Candida hyalinum infections in London, England. J Medical species in nail disease. Br J Dermatol 1988; 118: 47-58. Veterinary Mycology 1986; 24: 219-239.

163