I don't know what symptoms would give you spots and have you foam at the mouth. Could poison do that? In I, claudius, it was suggested he was poisoned or frightened to death. As for cipio's question about what would happened if Germanicus took over the empire after Tiberius left and all, if he got rid of Sijanus, things would have been much more stable, but that's from the personality I got from the movie about claudius.