Fever and rash in 18 year old any ideas?

Go to doctor. Go to the hospital! this could be a life threatening infection or something not too worrisome. Rule of thumb: fever + rash = seek medical attention, especially in a teenager.
Probably viral. The most common cause of a rash accompanied by a fever is a viral illness; but there are many other possibilities. Teens don't tend to run a fever unless something fairly significant is going on, so you should have him or her evaluated by your doctor or a dermatologist.

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My 6 year old present with an itchy rash and fever. Yesterday complained about a sore throat.?

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