In this multicenter cross sectional study, We found that the prevalence of current asthma, allergic rhinitis and eczema were 12%, 15.7% and 9.7% among 6–7 years age group in Kandy district while it was 15.3%, 30.5% and 7.3% respectively among the 13–14 age group. The reported prevalence rates of current asthma, allergic rhinitis and eczema were 9.9%, 10.1% and 5.9% among 6–7 years age group in Anuradhapura district. In addition to that, the prevalence rates of current asthma, allergic rhinitis and eczema were 14.9%, 22.5% and 1.8% in the 13–14 years age group from Anuradhapura district. When comparing these prevalence rates, there is relatively a higher prevalence of childhood allergic diseases in Kandy district. This difference is statistically significant for all three allergic disease conditions (P < 0.001).

There is a difference in asthma confirmed by a doctor in Kandy and Anuradhapura districts while it is not as such for others. This seems allergic diseases being under diagnosed in some areas which warrant further evaluation.

There are only a few local studies on the prevalence of allergic diseases in children of similar age groups. A similar study conducted in the western province has revealed a prevalence of asthma as 17%, Allergic rhinitis 21.4%, and eczema as 5% in a representative sample of children studying in grade 5 (age 10 years)[16]. When comparing these results with the present study, Anuradhapura district results are in parallel with the western province results while there is a deviation in Kandy district results. Another study conducted in Chilaw area (Gampaha district from western province) of Sri Lanka has reported a 17% of asthma prevalence rates and 22% of allergic rhinitis [17]. These results indicate there is a diversity of the prevalence rates among different geographic regions.

In our study, the overall prevalence of current allergic rhinitis in the 6–7 year and 13–14 year age groups are 12.9%, 26.5% respectively. It is higher than the mean of global prevalence (9.1%, 16%), and the Asia–Pacific prevalence of AR (5.8% and 14.5%) [14]. In addition to that, the overall prevalence of current eczema symptoms in the 6–7 years and 13–14 years age groups are 7.8%, 4.6% respectively. There are certain deviations when comparing these findings with the mean global prevalence (7.9%, 7.3%) and the Asia–pacific prevalence of eczema (4.7% and 5.3%) [3].

When comparing our results with other countries in the world, the developed countries have reported high prevalence of allergic diseases. Asher et al. have revealed a range of 20–37.6% prevalence of childhood allergic diseases in England, Australia and certain regions of US [1]. However, the rates are lower in the Asian region; India 6.4%, Pakistan 11.7%, Indonesia 5.2% [1].

The reported prevalence of wheeze in the present study is relatively high when comparing with other countries in the region; India 6.4%, Pakistan 11.7%, Indonesia 5.2% [1]. The reported prevalence of allergic rhinitis is slightly higher than that reported from the countries in the region: India 10%, Indonesia 4.8% and more or less similar to Pakistan 16.8%. With respect to eczema, Sri Lanka appears to have an approximately similar prevalence to India (3.7%) but lower than that of Pakistan (13.2%) [1].

The difference of the prevalence rates of allergic diseases in the two districts might be attributed to several factors. Kandy is an urban city where there is a poor air quality index due to the geographical location and traffic congestion [14]. This might be responsible for the higher prevalence of allergic diseases among the study groups than to Anuradhapura. A recent study conducted in China has also revealed that climatic variation and air pollution were associated with childhood allergic diseases [18]. In contrast, Anuradhapura has a relatively cleaner air quality [14]. Also Kandy is situated in the wet zone of the country while Anuradhapura situated in the dry zone of the country (Fig. 2). This climate changes may also need to be considered. In addition to that, urbanization, temperature, humidity, and regional differences could be linked to variations in prevalence [19]. On the other hand Kandy being second city in Sri Lanka and being an urban city, it has more accessible medical institutions around the clock compared to Anuradhapura being a rural district. Also road and accessibility is higher in Kandy vs Anuradhapura. However, further research is essential to support these speculations.

Limited response rate for certain questions in the questionnaire was identified as a limitation of the present study. This can be attributed mainly due to conducting the study during unusually harsh monsoon season and during post- year end-examinations where student attendance is generally low. Self-reporting for 13/14 year olds is a potential confounder, as is the inability to distinguish AR from NAR in this study. NAR might be more prevalent in polluted areas as well, further compounding this issue.