Bumpy, mostly-round rashes on the extensor surfaces of the legs usually mean erythema nodosum. The patients usually complain more of mild pain than itchiness. The lesions are a little tender when you push on them. It is one of the rashes that after you’ve seen once, the next ones are easy. There are many causes. The big two are sulfa drugs and strep infections. They usually require a derm follow-up (they almost always biopsy them for some reason). I stopped the bactrim and re-started the keflex based on past sensitivities. Ibuprofen helps. The rash slowly went away.
I wanted to talk about this case mostly about follow-up. Track down what happens to your patients. This patient went to derm, was biopsied, and the path dx was erythema multiforme. Save your mr numbers.