A 7-month-old boy is brought to clinic for an intensely pruritic rash that has been worsening over the past 2 months. His parents report frequent scratching that disrupts sleep. He has a history of wheezing with viral illnesses, and his mother has allergic rhinitis. Physical examination shows erythematous, scaly plaques with excoriations predominantly on the cheeks, scalp, and the extensor surfaces of the elbows and knees. There is no honey-colored crusting. Which of the following distributions is most characteristic of this condition across different age groups?