A Study of the Medicine Called Abrocitinib in Children 6 to Less Than 12 Years of Age With Moderate-to-Severe Eczema

This research study is being conducted to find out if the test medicine, abrocitinib, improves eczema and is safe for children 6 to \<12 years of age who have moderate-to-severe eczema. Research study participants who meet the study criteria will be assigned by chance (like the flip of a coin) to receive either abrocitinib test medicine or placebo (pretend medicine that looks just like the test medicine) for 16 weeks. The study will last for about 24 weeks in total.