A 5-month-old boy was brought to the doctor by his father for a rash that developed over the last 3 days. Before the lesion presentation, the boy and his family visited relatives in South Florida for their summer vacation and spent a few days at a beachfront resort in a hot climate. The patient appeared well and no other family members were affected. On examination, a deep pink, erythematous, macerated and crusted plaque was seen on the boy’s axillae in an intertriginous and bilateral distribution.
What’s the diagnosis?