A 4-month-old infant is brought to the clinic for a rash that began 2 weeks ago. The parents report intense itching and frequent scratching, especially at night. The infant has a history of intermittent wheezing and the mother has allergic rhinitis. Exam shows erythematous, scaly plaques with excoriations on the cheeks and extensor surfaces. There is no fever. The parents have been bathing the child daily with scented soap. Which of the following is the most appropriate first-line therapy for this patient’s condition?

(Age-appropriate preventive counseling is also desired.)