In 1991 I was camping in southern MO and went swimming in a river. The evening temp. was 93 degrees and we slept practically naked throught the night because it was so hot. The next day I had an unusual body rash mainly on my neck, arm pits, torso, inner thighs and inside elbow and back of knees. I blamed it on the heat. Saw a country doc and didn't know what to do. From that point on, I get this strange rash about every 4 or 6 months every year, after I have gone to sleep with a slight headache and slight joint pains and wake up feeling fine but have the same type of rash on my body. No one knows why. I don't feel sick, just a little achy before I go to sleep. The rash is very intense in color (bright red) with a slight raise, the morning after. It becomes more intense if I shower immediately upon waking up and it last for two days, generally, depending on the intensity of the rash. I don't know that I run a fever because I don't feel sick and therefore don't take my temperature but I do have chills before I fall asleep and go into a deep sleep and wake up 4 or 5 hours throwing all the blankets and my clothes off. Then I wake up with the rash. Strange no one seems to know what is causing this frequent pattern for the past 20 years. Do you have any ideas?