Some studies have reported the prevalence of atopic dermatitis in China. For instance, the ISAAC Phase I study reported a prevalence rate in 1995 of 1.2% among children aged 13–14 years [1]. The ISAAC Phase III study reported a rate of 0.9% in 2001 in the same age group [3]. In addition, Wang et al. reported prevalence rates in the same age group of 1.3% in 1994–1995 and 2.2% in 2001 [4]. A 2016 report showed that the prevalence rate was 10.39% among children aged 6–7 years in many parts of China [5]. The prevalence rate of our survey in Yixing (between Nanjing and Shanghai), China, in 2005 was 2.63% among children in this age group [6]. In particular, in Lhasa (the central city of Tibet), the prevalence rate was 0%. A similar result (0.2%) was reported in the ISAAC Phase III study in 2001. These data suggest that the environment of Tibet may provide clues regarding the prevention of atopic dermatitis.

The above data indicate that until around 2005, the prevalence of atopic dermatitis in China was very low, but increased rapidly from 2005 to 2016. This timeline is consistent with the rapid development of the economy of China over the same period, suggesting that factors associated with the rapid economic growth may have contributed to the increase in the prevalence of atopic dermatitis. However, China includes peoples of various racial backgrounds, socioeconomic statuses, and customs and has a variable climate. Thus, to better understand the increasing prevalence of atopic dermatitis, there is a need for more investigations among the same group or groups.

There are several studies that have investigated the prevalence of atopic dermatitis in Taiwan. The ISAAC Phase I study reported prevalence rates in 1995 of 3.5% and 1.4% among children aged 6–7 and 13–14 years, respectively [1]. In contrast, the ISAAC Phase III study reported rates in 2001–2002 of 7.5% and 4.2% among the same age groups, respectively [3]. Furthermore, Lee et al. reported that rates among children aged 12–15 years were 2.4% in 1995–1996 and 4.0% in 2001 [7]. They suggested that the increase was due to changes in the indoor environment, such as temperature and humidity, but that these factors were not major contributors to the observed increase. Additionally, Liao et al. reported prevalence rates of 1.1% in 1987, 1.9% in 1994, and 3.4% in 2002 among children aged 6–15 years, representing an increase of 3.05-fold over the previous 15 years [8]. They suggested that the increased prevalence of atopic eczema may be due to a decline in breast-feeding, the early introduction of weaning foods, and the widespread use of food additives. They also reported that atopic dermatitis is more prevalent in higher social classes and that rapid urbanization, including a more westernized lifestyle and a higher standard of living and education, may explain the rapid increase of atopic dermatitis. Finally, Yan et al. reported prevalence rates in 1994–1995 and 2001–2002 of 1.4% and 4.1%, respectively [9], in children aged 13–14 years, thus showing the same tendency toward an increasing prevalence rate between 1994 and 2002. However, more recent data regarding the prevalence rate are unavailable;, thus, there is a need for further investigations.

There are several studies that have investigated the prevalence of atopic dermatitis in Korea. The ISAAC Phase I study reported prevalence rates in 1995 of 8.8% and 3.8% among children aged 6–7 and 13–14 years, respectively [1]. The ISAAC Phase III study reported rates in 2001 of 11.3% and 5.7% in the same age groups, respectively [3]. Moreover, Oh et al. reported prevalence rates among children aged 6–12 years of 7.3% in 1994–1995 and 10.7% in 2001–2002 and among children aged 12–15 years of 3.5% and 6.1%, respectively [10]. In contrast, the same study reported the prevalence rate of food allergy was not significantly different from 1995 to 2000, indicating a poor correlation between the prevalence of atopic dermatitis and that of food allergy. Furthermore, in 1994–1995, Kim et al. reported prevalence rates of atopic dermatitis of 17.5% for urban, 9.6% for rural, and 4.0% for industrial areas among children aged 6–8 years; among children aged 10–12 years, these rates were 6.7%, 6.5%, and 3.5%, respectively [11]. The total prevalence rate for children aged 16–18 years was 6.0%. Using national statistics, including hospital- and clinic-based clinical information, Yu et al. reported that the prevalence rates from 2003 to 2008 decreased from 4.2 to 4.0%, respectively [12]. These data suggest that the prevalence rate in Korea peaked after 2008. In contrast, Kim et al. reported prevalence rates in 2009 on Jeju Island (off the coast of Korea) of 11.9% among children aged 6–9 years and 7.5% among those aged 9–12 years, with a total prevalence rate of 9.5% [13]. Moreover, Hong et al. reported prevalence rates in 2010 of 16.7% and 14.5% among children aged 7–9 and 10–13 years, respectively, and that the treatment frequency was 13.2% and 11.4%, respectively [14]. The lower treatment rates suggest that atopic dermatitis patients, especially those with mild disease, do not visit the hospitals or the clinics for treatment. This illustrates that medical institution-based surveys may have a limitation in that they may underestimate the prevalence rate of atopic dermatitis.

In Singapore, controversial findings regarding the prevalence of atopic dermatitis have been reported. The ISAAC Phase I reported prevalence rates in 1995 of 2.8% and 3.4% among children aged 6–7 and 13–14 years, respectively [1]. In contrast, the ISAAC Phase III study reported rates of 8.9% and 9.2% among the same age groups, respectively [3]. Tay et al. reported rates of 22.7%, 17.9%, and 21.5% in children aged 7, 12, and 16 years, respectively [15]. They also reported high prevalence rates of allergic rhinitis and asthma. They concluded that the reason for the high prevalence rate of atopic dermatitis may be the rapid urbanization of the city state of Singapore, its westernized lifestyle, and a high standard of living and education. Goh et al. reported prevalence rates in 1994 of 8.8% and 9.5% among children aged 6–12 and 12–15 years, respectively [16]. In contrast, Wang et al. reported prevalence rates in 2001 of 11.0% and 11.6% in the same age groups, respectively [17], indicating that the prevalence rate in Singapore was increasing. As a more recent rate has not been reported, there is a need for further investigations.

Only one study regarding the prevalence of atopic dermatitis has been reported in Malaysia. The ISAAC Phase I study reported prevalence rates in 1995 of 8.5% and 8.0% among children aged 6–7 and 13–14 years, respectively [1]. The ISAAC Phase III study reported rates in 2001–2002 of 12.6% and 9.9% among the same age groups, respectively [3]. In addition, Quah et al. reported rates in 1995 of 14.0% and 12.1% among the same age groups, respectively; they also reported rates in 2001 of 17.6% and 13.4%, respectively. They discussed that, except for atopic dermatitis, there were no major changes in the symptoms of asthma and allergic diseases in this community between 1995 and 2001. This indicates that air pollution, which induces asthma, may not be important for inducing atopic dermatitis.

There are several studies that have investigated the prevalence of atopic dermatitis in Thailand. For instance, the ISAAC Phase I study reported prevalence rates in 1995 of 11.9% and 8.2% among children aged 6–7 and 13–14 years, respectively [1]. In contrast, the ISAAC Phase III study reported rates of 15.6% and 9.9% among the same age groups, respectively, indicating that the prevalence rate in Singapore increased over this period [3]. As a more recent rate has not been reported, there is a need for further investigations.

There are few studies reporting the prevalence of atopic dermatitis in India. The ISAAC Phase I study reported prevalence rates in 1997 of 2.7% and 3.8% among children aged 6–7 and 13–14 years, respectively [1]. The ISAAC Phase III study reported rates in 2001–2003 among the same age groups, respectively [3]; however, because of an expansive national territory with various climate and customs, the variability of the prevalence rate in each city is very large. For example, prevalence rates in 2001–2003 among children aged 6–7 years ranged from 0.9% to 6.2%. In addition, Grills et al. reported a prevalence rate of dermatological disease in north India of 9.2% among all ages [18], though the rate among children was not reported. Interestingly, their report also showed a high prevalence rate of both atopic dermatitis and skin infectious disease. This result disagrees with the hygiene hypothesis. However, in India, owing to the scarce data, it is difficult to evaluate trends regarding the prevalence of atopic dermatitis, thus more nationwide investigations are needed.

There are few studies reporting the prevalence of atopic dermatitis in Iran. The ISAAC Phase I study reported prevalence rates in 1997 of 1.1% and 2.6% among children aged 6–7 and 13–14 years, respectively [1]. The ISAAC Phase III study reported rates of 3.2% and 4.2% in 2001–2003 among the same age groups, respectively [3]. Furthermore, Farajzadeh et al. reported rates in 2009–2010 of 13.5% and 8.3% among children aged 2–7 and 7–12 years, respectively [19]; however, this survey was conducted in Kerman, a desert area, where a low prevalence was expected. In other non-desert areas of Iran, the prevalence rate was 2.1% among children aged 6–12 years in Shahrekord (a city in southwest Iran) and 3.9% among children aged 7–11 years in Ahwaz (a city in southern Iran). These data suggest that prevalence was high in the desert area. The authors provided the following explanation. First, Kerman has a special geographic condition as it is located near Kavir Loot, one of the largest desert areas in Iran. In addition, Kerman has dry, sunny, and hot weather in contrast to the hot and humid weather of Ahwaz. Second, low humidity has a demonstrated effect on exacerbating and provoking atopic dermatitis. In contrast, indoor relative humidity is negatively associated with eczema symptoms. Third, furthermore, the ethnic origin of the population of Kerman is mainly Persian, whereas in Ahwaz, it is mainly Semitic.

Only one study regarding the prevalence of atopic dermatitis has been reported in Kuwait. Based on the ISAAC study, Owayed et al. reported prevalence rates of in 1995–1996 and 2001–2002 of 11.3% and 12.8%, respectively, among children aged 13–14 years, suggesting that the prevalence rate was high and did not increase [20].