Analysis of seasonal tendencies in pediatric Henoch–Schönlein purpura and comparison with outbreak of infectious diseases

Hwang, Hyun Ho; Lim, In Seok; Choi, Byung-Sun; Yi, Dae Yong

In the analysis based on age groups, the infant, early childhood, and middle childhood groups had the most patients in March (Spring) and least in August (summer) ( Table 2) . Among the adolescents, most cases of HSP were reported in April (479 patient, 12.0%) and spring (1302 patients, 32.7%). However, unlike in the other age groups, among adolescents, 290 (7.3%), 237 (6.0%), 254 (6.4%), and 269 (6.8%) patients were diagnosed in August through November, respectively. More patients were diagnosed in the summer (985 patients, 24.8%) than in the fall (760 patients, 19.1%). Figure 2 shows the monthly, seasonal, and yearly analyses of the patterns of respiratory and gastrointestinal virus epidemics. The positive detection counts for most viruses showed apparent seasonal variations. However, adenovirus appeared to have a fairly uniform pattern throughout the year and did not show any special outbreak. RSV showed a definite tendency from November to January, while the influenza virus was prevalent in winter from January to April. On the contrary, parainfluenza virus showed a tendency in the late spring and early summer such as May or June. The positive detections of coronavirus and rhinovirus were highest from November to January and from October to November, respectively. Rotavirus detection was highest from February to April while detection of norovirus was highest from November to January. However, in the cases of bocavirus, metapneumovirus, enteric adenovirus, and astrovirus, the monthly incidences were low, and it was difficult to identify epidemic patterns. Nevertheless, bocavirus was more prevalent in late spring and early summer than in other seasons and was highest from May to June, while metapneumovirus was more prevalent in April and May.