For years I have had large patches of psoriasis or eczema on my shins. Had steroid creams off GP when it got really bad. Mainly used E45 etc as routine.
Because of my weight, recently went on a strict diet. Hardly any meat, no alcohol, lots of vegetables and some fruit etc every day.
Weight coming off slowly because of inactivity, due to other health problems, but the scaly skin on my shins has completely disappeared.
Really happy about it.
Can you suggest what possible evolutionary advantage psoriasis might give to any individual human? Whatever that advantage might be, that is what you would interpret as god's goodness. Just enjoy.