Pediatric AD imposes an enormous burden on children and their families.8 Topical PDE4 inhibitors, including OPA‐15406, have been evaluated for the treatment of patients with AD, and further development is currently ongoing.27 This phase 2 study evaluated the safety and efficacy of topical OPA‐15406 in Japanese pediatric patients with AD aged 2–14 years. Here, PDE4A is linked to Alzheimer disease.