Warts are one of the most chronic and frustrating skin and mucosal conditions encountered in dermatology clinics . Despite variable reported prevalence rate in primary school children, warts in this age seem to have an even higher prevalence than in adults. In our study, we reported a total prevalence of warts, 10.3%. This agrees with the finding reported in Medinah and Jeddah regions, Saudi Arabia . On the other hand, a much lower prevalence rate (4.5%) was reported in Al Hassa rural area, Saudi Arabia , whereas a higher prevalence (13.1%) was reported in Kuwait .
Some studies from other areas in the world reported variable results. The prevalence of warts in primary school children in Romania and Taiwan was 6.9%, 2.4%, and 2.8% , respectively [12,13,14]. The highest reported prevalence was 33% among Dutch primary school students .
The difference in the prevalence rate of warts between different studies may reflect the difference in sociodemographic patterns and distribution of risk factors among studied children in addition to differences in the inclusion criteria of the target population.
In the present study, neither age nor sex showed a statistically significant difference regarding wart prevalence. On the other hand, some other studies reported a higher prevalence in older age groups from 8 to 12 years [15, 16] or with male sex  as males are more exposed to outdoor activities that may carry a risk for infection such as exposure to water channels, manure, and animals.
Common wart was the most prevalent type in our study. This is in line with the majority of published studies in school children [5, 15, 17] with some exceptions that reported higher percent of affection with plantar warts than common warts .
Fortunately, genital warts had the lowest percent in our study (2.8%) despite it was reported to be the second prevalent type in children after common wart in a study in Kuwait  where the presence of foreign babysitters and servants from different nationalities is more common  than that in Egypt.
Genital warts are of special importance since children with genital warts will often raise the suspicion of child sexual abuse . However, several studies indicate that the origin of pediatric anogenital human papilloma viral infections remains often untraced (innocent warts), with no indication of sexual abuse .
The hand was the most commonly affected site in our study. This agrees with many other studies [15, 17, 20]. Hands are the most common site that had a high likelihood to contact a contaminated environmental surface during play or work besides the natural tendency for children to pick or scratch at existing warts.
The impact of socioeconomic status on the prevalence of warts is evident in our study as the prevalence was higher in children from rural areas, public schools, and big families. Similar results were also reported in many other studies [9, 10, 18, 21]. Factors like overcrowding, lower hygiene with sharing of personal fomites, and reluctance to seek medical advice are more common in children from rural areas, public schools, and big families which reflect lower socioeconomic level. Also, the level of paternal and maternal education and work status had an impact on wart prevalence as high education, skilled father work, and working mothers were associated with a low prevalence of warts. This was concluded in many other studies [2, 9, 10, 21].
Education and socioeconomic state of the individuals certainly affect health awareness and standards of hygiene within the family; educated parents will seek medical advice if their son/daughter has wart [22, 23]. Although this attitude is less likely to decrease wart incidence, it may decrease wart prevalence through shortening the disease duration .
Exposure to water channels, walking barefoot on soil, and sharing shoes with other family members were significant associated factors for wart infection in our study. These factors are more common in rural areas and big families. The results of other studies about these risk factors were contradictory [2, 15, 18].
However, studies on environmental risk factors for warts are contradictory and all have a cross-sectional design where the causal influences of the risk factors could not be exactly determined.
Definite positive family contact could be detected among 37% of the affected students in our study. Unfortunately, we could not get definite information about the presence or absence of positive family contacts in non-affected children, so we could not obtain an odds ratio for that risk factor. Two studies reported that the presence of positive family contacts is the major positive predictor for wart prevalence in school children regardless of other environmental factors such as use of public swimming pools, practice sports barefoot, and use of public showers [1, 18].
By regression analysis of different associated factors, big family size was a significant associated factor for wart infection in our study. The same finding was also concluded in many other studies [2, 9, 10, 18, 21]. Another significant associated factor was sharing shoes with other family members (22.7%) which is also more likely to occur in large families and low socioeconomic level.
Limitations of the study
Data on the risk factors were collected by recall which may be subjected to some bias. The results represent the prevalence in Tema District and cannot be generalized to Sohag Governorate as a whole.