Background During COVID-19, studies have reported the appearance of internet searches for disease symptoms before their validation by the World Health Organization. This suggested that monitoring of these searches with tools including Google Trends may help monitor the pandemic itself. In Europe and North America, dermatologists reported an unexpected outbreak of cutaneous acral lesions (eg, chilblain-like lesions) in April 2020. However, external factors such as public communications may also hinder the use of Google Trends as an infodemiology tool. Objective The study aimed to assess the impact of media announcements and lockdown enforcement on internet searches related to cutaneous acral lesions during the COVID-19 outbreak in 2020. Methods Two searches on Google Trends, including daily relative search volumes for (1) “toe” or “chilblains” and (2) “coronavirus,” were performed from January 1 to May 16, 2020, with the United States, the United Kingdom, France, Italy, Spain, and Germany as the countries of choice. The ratio of interest over time in “chilblains” and “coronavirus” was plotted. To assess the impact of lockdown enforcement and media coverage on these internet searches, we performed an interrupted time-series analysis for each country. Results The ratio of interest over time in “chilblains” to “coronavirus” showed a constant upward trend. In France, Italy, and the United Kingdom, lockdown enforcement was associated with a significant slope change for “chilblain” searches with a variation coefficient of 1.06 (SE 0.42) (P=0.01), 1.04 (SE 0.28) (P<.01), and 1.21 (SE 0.44) (P=0.01), respectively. After media announcements, these ratios significantly increased in France, Spain, Italy, and the United States with variation coefficients of 18.95 (SE 5.77) (P=.001), 31.31 (SE 6.31) (P<.001), 14.57 (SE 6.33) (P=.02), and 11.24 (SE 4.93) (P=.02), respectively, followed by a significant downward trend in France (–1.82 [SE 0.45]), Spain (–1.10 [SE 0.38]), and Italy (–0.93 [SE 0.33]) (P<.001, P=0.004, and P<.001, respectively). The adjusted R2 values were 0.311, 0.351, 0.325, and 0.305 for France, Spain, Italy, and the United States, respectively, suggesting an average correlation between time and the search volume; however, this correlation was weak for Germany and the United Kingdom. Conclusions To date, the association between chilblain-like lesions and COVID-19 remains controversial; however, our results indicate that Google queries of “chilblain” were highly influenced by media coverage and government policies, indicating that caution should be exercised when using Google Trends as a monitoring tool for emerging diseases.

BACKGROUND External factors may hinder Google Trends (GT)’s role as an infodemiology tool. For COVID-19, new symptoms and their searches on internet prior to world organization of health validation were previsouly described. In western country, an unexpected outbreak of cutaneous acral lesion e.g chilblains was released by the dermatologists in April. OBJECTIVE The aim of the study was to assess the temporality between media announcement or lockdown and online searches related to cutaneous acral lesion during COVID-19 outbreak. METHODS Two searches on GT including daily relative search volumes related to 1/ “toe” or “chilblains” and 2/ “coronavirus” were made from January 1st to May 16th 2020 for US, UK, France, Italy, Spain, and Germany. The ratio chilblains to coronavirus was plotted. To assess the impact of lockdown and media coverages, interrupted time series analysis were performed for each country. RESULTS During the period the ratio chilblains /coronavirus searches showed a constant upward trend. In France, Italy and UK, the lockdown was associated to a significant slope change of chilblain searches with coefficient value of 1.06  0.42, 1.04  0.28 and, 1.21  0.44 (p<0.01) respectively. After media announcement, a steep statistically significant increase was found in France, Spain, Italy and the US with coefficient values of 18.95 5.77, 31.31  6.31, 14.57  6.33, 11.24  4.93 (p<0.01), followed by with a statistically significant downward trend in France, Spain and Italy (p<0.01). Adjusted R2 values were 0.311, 0.351, 0.325, 0.305 in France, Spain, Italy and US, in favor of an average correlation between time and research volume. The correlation was weak in Germany and UK. CONCLUSIONS To date chilblains link to COVID-19 remains controversial in the scientific community. However their relative search volumes on GT were highly influenced by lockdown measures and media coverage suggesting caution when using GT as pandemic surveillance tool.

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