My husband periodically presents with a feeling of general unwellness,lightheaded feeling ,low grade fever ,and weakness.After about 6-10 hrs of this he develops a rash all over his saddle area(lower back- buttocks ) It is very hot to the touch,lasts several days,is painful,then begins to itch and peel.At no time is it bumpy or uneven,just massive and red all over.Any thoughts?