opportunistic infection - any infection caused by a microorganism that does not normally cause disease in humans; occurs in persons with abnormally functioning immune systems (as AIDS patients or transplant patients receiving immunosuppressive drugs)
Why your 'flushing' could be a red alert to see your doctor. It is a normal body response that may occur when we are embarrassed, angry, excited, or experiencing other strong emotions. But 'flushing' - when the face, ears, neck and, occasionally, upper chest, take on a red colour, accompanied by a hot feeling - can also be a sign of a more serious underlying condition.
To cause to be full; to flood; to overflow; to overwhelm with water; as, to flush the meadows; to flood for the purpose of cleaning; as, to flush a sewer. 2. To cause the blood to rush into (the face); to put to the blush, or to cause to glow with excitement. Nor flush with shame the passing virgin's cheek.