A 6-Year-Old Boy With Cough, Mucositis, and Vesiculobullous Skin Lesions

A 6-year-old boy taking no regular medications had persistent fever and cough for 15 days. Physical examination revealed eyelid swelling; vesiculobullous lesions on the palms and soles; vesicles and erosions on the face, trunk, and limbs; erosions on the lips and oral mucosa; and blisters on the anal mucosa. Laboratory testing revealed leukocytosis, and lung auscultation revealed bilateral crackles. What is the diagnosis and what would you do next?