Also Infects Dolphins

You volunteer with a medical mission to see outpatients in a clinic in Brazil (or Colombia, Suriname, Venezuela, Guyana, French Guiana, Ecuador, Peru, Bolivia, Costa Rica, or Mexico). You get a rash (pun not intended) of forest workers, farmers, hunters, and fishermen between 40 and 70 with the following findings:

The histology is shown below:

Challenge: What's your diagnosis?

First three images shown under Fair Use. Fourth image is in the public domain.