Tinea Capitis among Iraqi Children: Public Health Implication

Prof. Dr. Abdul Ghani Mohamed Al Samarai. Department of Medicine, College of Medicine, Tikrit University, P O Box 45, Al Yarmouk ST., Tikrit, Iraq

Abstract

Background: Recent observations on tinea capitis cases in Iraq suggest that there has been a change in the pattern of infection, with a recent and significant rise in the incidence of infection due to anthropophilic dermatophytes.
Objectives:The purpose of this study was to investigate the incidence rate and identify factors that might affect the spread of infection of tinea capitis in Iraq.
Patients and Methods: There were 40,384 children from 6 to 16 years of age included in the study. The children were from two different geographical areas.
Results: The prevalence rate of clinically diagnosed tinea capitis was 1.25%, while the mycological prevalence rate was 0.86%. The above difference between clinical and mycological prevalence rates was statistically significant (P < 0.001). In addition, the prevalence rate was significantly higher (P < 0.05) in males (1.08%) as compared to females (0.96%) and in rural areas (2.06%; P < 0.0001) as compared to urban (0.62%) areas. Animal contact and family history of tinea capitis were important risk factors in disease transmission. The prevalence of tinea capitis was 86.3% in age group of 6–10 years (P < 0.0001). The non-inflammatory type of infection was found in 87.5% of cases (P < 0.0001). The frequency of isolation of anthropophilic dermatophytes was reported in 73.3% of cases (P < 0.001). The predominant causative agent was Trichophyton tonsurans (26%), followed by T. verrucosum (25.1%). The isolated species was distributed in urban and rural areas.
Conclusion: This study indicated a shift in the epidemiologic patterns of tinea capitis in Iraq. T. tonsurans was the most prevalent cause of tinea capitis in Iraq. There was a significant role for influence of infection for sex, residence, animal contact, and hair type.

Tinea capitis, Iraq, children

Introduction
Tinea capitis has a worldwide distribution (1) and tends to be epidemic and endemic in areas where crowding and imperfect conditions for personal hygiene seem to favour its spread and persistence within the community (2). The prevalence of infection varies considerably with geographical location and climatic condition (3). Many studies that have been conducted throughout the world revealed the increased prevalence and shift in the epidemiology of tinea capitis (4),(5),(6),(7),(8),(9)and(10). Geographic locations are important factors in the type of infection seen (3),(4),(5),(6),(7),(8),(9),(10),(11),(12),(13),(14)and(15).

Material and Methods

Objectives
The objectives of this study are to
1.determine the demographic and clinical characteristics of tinea capitis in Iraq;
2.identify the etiological dermatophytes for tinea capitis in Iraq.

Study Population
A cross-sectional community study was performed, and two groups of schools were chosen. The first group was distributed in urban areas, and the second group was selected from different rural areas in Tikrit and Kirkuk governorates. For Tikrit survey two groups of schools were chosen: the first group from urban areas and the second from differing rural areas in the vicinity of Tikrit. Three boys’ schools, three girls’ schools, and two large mixed schools were randomly selected from five urban areas of Tikrit. Six schools from four rural villages were chosen: two boys’, two girls’, and two mixed schools. Tikrit survey was conducted between September 1994 and April 1995, and a total of 4461 children were included in the survey. The second survey was carried out in Kirkuk from September 1996 to May 1997. In urban areas 131 schools were selected, of them 24 were girl’s schools, 20 boys’ schools, and 87 mixed schools. In rural areas 20 schools were selected: eight boys’ schools, three girl’s schools, and nine mixed schools. A total number of 35,923 children were included in the survey. The criteria for their selection were the same as described previously (14),(15). The children were all preadolescent school-age children. Their ages range from 6 to 16 years. Since both surveys were with the same design, the data of both were combined together and reanalyzed to get an idea about the pattern of tinea capitis in Iraq. All the students in the school were examined, so a total of 40,384 students were included in the study. The scalp of each child was thoroughly examined in all areas for evidence of scaling, crusting, follicular inflammation, hair loss, and erythema. Clinical diagnosis of tinea capitis was done according to criteria of Arnold et al. (11).

Sample Collection
In all suspected cases, hairs and scales were collected for mycological examination by a conventional technique. Scale scrapings were collected from at least two areas with a number 15 sterile surgical blade, and approximately 12 hair stumps (roots) were pulled out with sterile epilator forceps. Both hairs and scales were placed in a clean, labelled envelope and sent to the laboratory for investigation.


Laboratory Procedures and Identification
Media used for primary isolation of dermatophytes, maintenance, and identification were according to conventional reported procedures (16). Species were identified using conventional method, which emphasised colony morphology, microscopy, and other miscellaneous tests. Cultures were examined macroscopically for morphology, texture, and colour from the top and reverse sides of the plate. Then using a sterile straight loop the colony was examined by placing a sample on a drop of lactophenol solution on a clean glass slide. The matted mycelial mass was teased or separated with dissecting needles to facilitate microscopical observation. The preparation was then covered by a cover slip and examined under the microscope for the presence of microconidia, macroconidia, and other structures. Every positive growth obtained was subcultured on two Sabouraud plates, one with added yeast and the other with added sodium chloride. The inoculated plates were incubated for 2 weeks at 28°C to further stimulate the chlamydospores. After identification was completed, the plates were kept refrigerated at 4°C for a maximum period of 1 month.

In vitro hair perforation by certain dermatophytes was used for further species identification. This test was used to differentiate certain species of T. mentagrophytes, which can penetrate hair in vitro, from T. rubrum, which cannot.<

Results

The prevalence rate of clinically diagnosed tinea capitis was 1.25%, whereas the mycological prevalence rate was 0.86%. The above difference between clinical and mycological prevalence rate was statistically significant (P < 0.001). In addition, the prevalence rate was significantly higher (P < 0.05) in males (1.08%) as compared to females (0.96%) and in rural areas (2.06%; P < 0.0001) as compared to urban (0.62%) areas (Table/Fig 1).

Tinea capitis cases were more common in urban (59%) than in rural (41%) areas (P < 0.0001) and in males (70%) than in females (P < 0.05) (Table/Fig 2). The case frequency was 93.5% in children with history of animal contact, whereas the corresponding value was 31.3% in children without history of animal contact (P < 0.0001).

Normally, the frequency of infection was reported in all cases with a family history of tinea capitis; however, the infection was reported in 63% of children without any family history of disease (P < 0.0001) (Table/Fig 2).

The prevalence of tinea capitis was 86.3% in age group of 6–10 years (P < 0.0001). The prevalence of tinea capitis was lower in straight hair (33%), as compared to curly hair (67%, P < 0.001) (Table/Fig 3). Frontal site was the predominant (46%) site involved. The non-inflammatory type of infection was found in 87.5% of cases (P < 0.0001). The scaling was found to be the predominant clinical characteristic (59.1%). Seborrhoid was the most common clinical form (80.8%). Favus presented in 1.7% of cases (six cases); five of them were caused by T. violaceum and in one case the causative dermatophytes were unidentified.

The frequency of isolation of anthropophilic dermatophytes was reported in 68.1% of cases (P < 0.001). The predominant causative agent was T. tonsurans (27.6%), followed by T. verrucosum (26.7%). The isolated species was distributed in urban and rural areas.

In rural areas, the predominant isolate was T. verrucosum (33.3%), followed by T. tonsurans (21%) (Table/Fig 4). In urban areas, T. tonsuransforms the predominant (32.5%) isolate, followed by T. mentagrophytes var interdigitale (26.8%) ((Table/Fig 4)).

The isolated species were distributed in both sexes. In male, the predominantly isolated species was T. tonsurans (27%) followed by T. verrucosum (25.2%), whereas in female the predominantly isolated species was T. verrucosum (30.5%), followed by T. tonsurans (29.5%) (Table/Fig 4).

Discussion

This study has shown that the clinical prevalence rate of tinea capitis, in a large sample of primary school children in two different Iraqi governorates, was 1.25%. However, the mycological prevalence rate was significantly lower than clinical prevalence rate. Sex seems to play a role in infection, as the prevalence rate was more in male as compared to female. This male predominance of infection was also reported for other geographical areas (9),(17),(18),(19),(20) and (21).

The high rate of tinea capitis in male may be attributed to the easy implantation of spores because of short hair (22) and frequency of sharing comb, brushes, and cups (23). This study shows that the prevalence of tinea capitis was more in rural than in urban areas. This finding is in agreement with that reported before for different geographical areas in Iraq (24),(25)and(26). The high prevalence rate of the disease in rural areas may be due to low standard of living, low standard of health education, overcrowding, poor hygiene, close personal contact, animal contact, and no separation between animal house and their houses (26). Contact with animals seems to be an important risk factor that increases prevalence rate, as this study indicated higher significant rate in children with animal contacts than in children without animal contacts. This was also reported for other geographical areas outside Iraq (18),(19),(22).

Presence of tinea capitis in other family members also acts as an important source of infection. This is due to intra-familial transmission, and the home might be more likely a source of infection than the school (26),(27). These results are reported by others (17),(27),(28),(29)and (30). Hair type influences the infection rate, and thus the cases were more in children with curly hair. This could be due to difficulty in hair washing and cleaning, which provides stable and less hazardous environment for dermatophytes (1),(26),(31),(32). The predominant clinical form was seborrhoid, and the mostly affected site was frontal area of the scalp.

Concerning aetiology, the zoophilic dermatophytes were found as the cause of infection in 31.9% of cases. These zoophilic organisms are acquired through contact with infected animals, since a large number of families in the study areas were in contact with animals. Although human infections with zoophiles are of the supportive type, animal infection may be clinically silent and thus the animals serve as asymptomatic carriers (33). Anthropophilic dermatophytes were more predominant cause of tinea capitis. This may be due to the fact that anthropophilic infections are often epidemic in nature (33), and children are population at risk of anthropohilic tinea capitis (33),(34). Thus, prevention control programs for tinea capitis in children may need to take this in consideration when designing and performing their program. Primary school health programs for tinea capitis control must concentrate on primary school students who demonstrate higher prevalence rate (ages 6–10 years).

The predominantly isolated dermatophyte was ere T. tonsurans, and this finding indicated a shif

Conclusion

In conclusion, there were significant differences in prevalence rate in regards to gender, residence, animal contact, hair type, clinical characteristics, and clinical forms. The significant differences were detected in frequency distribution of dermatophytes as a cause of tinea capitis and their distribution in rural and urban areas and indicate a shift in epidemiologic patterns. However, the conclusion emerged from this study demonstrate the demographic and clinical characteristics of the disease in Iraq as a whole country.