Automate: Well, if you can get a text copy of his book, it isn't  hard to
isolate all structured components like section headings. IF these are diseases then
your work is done- sed, grep, awk etc. If the text is unstructured, you can still remove all the common words and probably isolate a list that is mostly dermatological conditions.However, in the latter case, it may be easier to get all the pubmed hits that mention "dematology" and do the same technique on the abstracts. This doesn't get every disease in every paper, but should get those central to each paper.