I thought this was a fascinating little story...I remember reading several books back in the day and Marat was a fascinating creature
...and now the clever kids have added a bit of info to the story

"Based on all the available evidence, we hypothesize that Marat may have suffered from a primary fungal infection (seborrheic dermatitis), superinfected with bacterial opportunistic pathogens."


...it sounds quite maddening...I have some minor 'old guy skin' issues and they can really drive you bonkers when it acts up so I can just imagine what he was going through...although some 'Karma' talk might also be appropriate if memory serves...