A 77-year-old boy has a bright-pink punctate rash against the background of hyperemia on his forehead, neck, lower abdomen, and in the popliteal spaces. His nasolabial triangle is pale. In the oropharynx there is a bright-red hyperemic area with clear margins, the tonsils are swollen and friable, lacunas contain pus, the tongue is raspberry pink. The cervical lymph nodes are enlarged and painful. Make the diagnosis: