We know that Prurisol caused remission in the rats
Post# of 72440
I could easily foresee a scenario where someone got the same dose for a mild case as for a severe case -- because Prurisol seems to work at the base layers of the skin, where new skin is formed. You'd want to make sure you knocked out the auto-immune problem that caused the bad skin to form. But, it's possible that a mild case could be a shorter course of treatment than a severe case. Or, as you say, possibly a smaller dose. If I were taking it though, I'd want to bomb it with medicine and be sure that the problem got stopped.
The next batch of data will tell us a lot more.