Can you identify these painful nodules in this boy's leg?

What's your diagnosis? For hints and clues, click here. Rash Decisions

(Case and image courtesy of Shannon Etheridge Whitten, MS, NP-C)
. Nonpruritic nonsuppurative painful erythematous nodules on the lower extremities of a 5–year-old boy. 

. The rash appeared about 1 week after the onset of a dry hacking cough.

. The child had a low-grade fever and joint pain, as well as effusions in his right knee and elbow.
Hints:Erythema multiforme MRSA Erythema nodosum Insect bite What’s your diagnosis?