I Am An MD. I Just Saw A Patient With

I am an MD. I just saw a patient with a purpuric rash on the right shin, fever (unmeasured, but he claims severe chills), nausea, vomiting and diarrhea. This rash (same place) has been recurrent for 20+ years since he came back from the Dominican Republic. He calls it malaria - but admits that no doctor has ever tested him for malaria. In questioning about the fever, it is not cycling or relapsing. He can't define it by timing at all. The rash intrigues me. Would this be at all characteristic of a leishmaniasis rash?? Can you think of any other tropical disease which might fit these recurring symptoms? Also - it appears to respond to Keflex.