Dermatophytes and Other Fungi Associated with Hair-Scalp of Nursery and Primary School Children in Awka, Nigeria
T Mbata, C Nwajagu
dermatophytes, dermatophytosis, hair-scalp, mycosis
T Mbata, C Nwajagu. Dermatophytes and Other Fungi Associated with Hair-Scalp of Nursery and Primary School Children in Awka, Nigeria. The Internet Journal of Dermatology. 2006 Volume 5 Number 2.
A total of 2,117 nursery and primary school children aged 1-13 years were surveyed for hair-scalp infection in Awka, Nigeria between January and March 2004. Specimens for mycological investigations were confirmed by microscopic examinations in 100 cases (4.7%) and the causative agents were isolated and cultured in 84 positive cases (3.9%). Zoophilic dermatophytes accounted for (42%) followed by geophilic (37%) and anthropophilic (21%) dermatophytes.
The superficial fungal infections or superficial mycoses affect the hair, nails and skin 1,2,3. On the skin and scalp, the lesions are often roughly circular with raised border, but may coalesce to form confluent areas of dry, scaling skin, inducing itching and scratching which in severe cases may ulcerate 4. The superficial mycoses include principally dermatophytes, pityriasis versicolar, tinea-nigra, black piedra, white piedra, cutaneous candidosis etc. Untold numbers of people world-wide suffer these infections. Sex, race and occupation have little recognized differential influence upon the frequency of these infections. Age, however influences susceptibility to dermatophytosis due to developed immunity5. Children are mostly affected by dermatophytic infection before and during puberty6. It is caused by a variety of zoophilic, anthropophilic and geophilic dermatophytes of the genera
The prevalence of superficial mycoses (
The present study is aimed at detecting the presence of dermatophytes and other fungi associated with hair-scalp of nursery and primary school children in Awka, Nigeria.
Materials and methods
The selection was carried out using the method described by Ellabid20. A total of 2117 children with an age range of 1-13 years suspected to have superficial hair-scalp infections were randomly selected from 4 primary schools in Awka, Nigeria between January and March 2004. Questionnaires and physical observations were used to obtain information on duration of the lesion, clinical picture, prior therapy as well as demographic data such as age, sex, nationality and family status of the respondents. The final selected culture positive children for this study consisted of 51 males and 33 females, including nursery children.
Two sample collection methods were used in this study: In one method, samples consisting of epidermal scales and infected hairs were scraped from the scalp/rim of lesions using a sterile scalpel blade following cleaning of the affected sites with 70v/v isopropyl alcohol. The scrapings were collected on a piece of sterile brown paper21. Moist cotton swabs were used to collect pus from inflammatory lesions. The samples were divided into two portions: one for microscopic examination and one for culture. The collected samples were transported to the laboratory within 2 hours for microscopic and cultural analysis. A second method was a brush culture collection technique described by Mackenzie.22
Direct microscopic examination
Direct microscopic examination of scales and broken-off hairs placed on a microscope slide with one or two drop of 20% potassium hydroxide (KOH) and a cover slip was performed. The sample was warmed for 5 minutes over a flame as described by Hainer4. Each treated slide was then carefully examined under low (X10) and high (X40) power objective for the presence of hyphae and/or arthroconidia.
Each scraping was cultured into sabouraud dextrose chloramphenicol actidione agar23. A duplicate inoculation of the specimen was also cultured on sabouraud's dextrose cycloheximide agar. The plates were incubated at 28°C for up to 4 weeks and examined at 2 to 3 day intervals for fungal growth. Fungal isolates were subcultured onto plates of sabouraud's agar, potato glucose agar and corn meal agar. The isolates were examined visually and microscopically for morphology of fungi using lactophenol cotton blue by slide culture technique. Yeasts were identified with the taxonomic criteria outlined by Lodder24. Each isolate was tested for the ability to ferment and/or assimilate different carbon sources. They were also tested for their ability to produce Urease, utilize HNO3 as the sole nitrogen source and grow at 37°C. The dermatophytes species were identified by gross and microscopic morphology and by
Samples were obtained 2117 children presenting with suspected superficial mycoses during the course of this study. Diagnosis was confirmed by microscopic examination in 100 cases (4.7%) and the causative agents were isolated in 84 cases (3.9%). From the total number of isolates identified, dermatophytes were the most prevalent.
Table 1 lists the species isolated, their frequencies and the sites where they were found. Many fungi belonging to 7 different genera were recovered from the hair-scalp of 84 of the 2117 children. The majority of the isolated dermatophytes were zoophilic (42%) followed by geophilic (37%) and anthropophilic (21%) dermatophytes.
Table 2 shows the pattern of distribution of infection by age. Analysis of the data showed that 47 children examined representing (47%) of the 100 children were between the ages of 5-9 years, while 23 (23%) were between 10-13 years and 30 (30%) were between 1-4 years.
Table 3 shows the distribution of fungal positive cases by sex. Among 84 culture positive children examined, 56 (66.7%) were male, while 28 (33.3%) were female.
Table 4 list the species isolates (etiological agents) from inflammatory lesions. The children's clinical picture varied: 64 children (76.2%) presented gray patches with broken-off hair near the follicle and 10 children (11.9%) presented diffuse scaling with hairs broken off at the follicle with or without black dots. In 9 children (10.7%) the infection was inflammatory with follicular pustules and kerion. Finally, one child (1.2%) had an atypical presentation as amiantacea and atrophic patches with clinically apparent alopecia.
The majority of the inflammatory disorders were mainly recovered in cases of
During the period of this study, samples were collected from 2117 children from 4 primary school districts and diagnosed as having a superficial fungal infection. Microscopic identification was performed in 100 cases and the causative agent was identified by culture in 84 cases.
Fungi are everywhere and no geographical area or any group of people is spared by these organisms. In Nigeria, superficial mycoses are among the commonest of infectious diseases and constitute the bulk of mycotic infections 15,16,17,27. However, accurate assessment of the prevalence of etiologic agents is useful to estimate the size of the problem and to prevent transmission.
The incidence of hair-scalp infections among nursery and primary school children in Nigeria found that dermatophytes were the most common cause of all culture positive fungal infections involving the hair-scalp observed during the period of this study. Of the isolated species
In this study children could have contracted the infection either by direct contact with infected children at school or indirectly by sharing infected facilities, including combs, towels, etc4. Other factors contributing to the transmission of infections include over crowding and poor sanitary environment4. This is a common practice in most primary schools in Nigeria and this may facilitate transmission.
Three anthropophilic species of dermatophytes
The role of pets (dogs) as reservoirs in transmitting dermatomycosis to children has been amply documented 31. In this study only 2 children (2%) had contacts with pets and were not aware of the danger of contracting dermatophytosis.
Certain factors may influence the distribution of dermatophytosis. Srejaard 32 suggested infection is influenced by environment and also by age and sex. We found that the highest incidence of infection occurred in younger children (47%) aged 5-9 years and (30%) in children aged 1-4 years rather than in older children > 10 years (23%).
According to Ekenem,5 age influences susceptibility to dermatophytosis because of the changes in immunity. In this study the children may have been immunosuppressed due to the high incidence of infection recorded. These results are in agreement with the work of Hainer4 that children with dermatophytes are usually otherwise healthy. However, chronic and extensive infections are common in children who are immunosupressed or with depressed cell-mediated immunity. In Nigeria, malnutrition is a predisposal factor and influences the prevalence of skin diseases (
Most infected children on physical examination reveal a characteristics pattern of inflammation characterized by a greater degree of redness and scaling at the edge of the lesion or occasionally blister formation as in the case of most dermatophytes identified(Table 1). Mucosal involvement with an adjacent red, scaly skin rash was seen in Candida infection.
The presence of other non-dermatophytes (particularly
The study showed that dermatophytes were the most common cause of all culture positive fungal infections involving the hair-scalp among children. However, there were no children with HIV-AIDS, and there is a need for children who are generally at risk to be aware of the dangers of contracting dermatophytes. The government should create greater awareness of environment and personal hygiene to help to curb the incidence.