A previously healthy 15-year-old boy came to the emergency department with severe prostration associated with a worsening rash. The eruption had begun as red macules on his palms 4 days previously and rapidly progressed to involve all areas of his skin. He also had painful ulcerations in his mouth and uncomfortable redness of his eyes.
On physical examination, he was lethargic and hypotensive, with a blood pressure of 80/30 mm Hg. Discrete and confluent erythematous patches and plaques, many of which were targetoid (Figure 1), involved 95% of his skin. There was distinct palmar involvement (Figure 2) and central facial swelling with bilateral conjunctivitis (Figure 3). He had ulcerations in his mouth and on his glans penis.
What is your diagnosis?