Blushing refers to the involuntary reddening of a person's face due to embarrassment or emotional stress, though it has been known to come from being lovestruck, or from some kind of romantic stimulation. It is thought that blushing is the result of an overactive sympathetic nervous system. Severe blushing is common in people who suffer social anxiety in which the person experiences extreme and persistent anxiety in social and performance situations.
Blushing is generally distinguished, despite a close physiological relation, from flushing, which is more intensive and extends over more of the body, and seldom has a mental source. If redness persists for abnormal amounts of time after blushing, then it may be considered an early sign of rosacea. Idiopathic craniofacial erythema is a medical condition where a person blushes strongly with little or no provocation. Just about any situation can bring on intense blushing and it may take one or two minutes for the blush to disappear. Severe blushing can make it difficult for the person to feel comfortable in either social or professional situations.
People who have social phobia are particularly prone to idiopathic craniofacial erythema. Psychological treatments and medication can help control blushing. Some people are overly sensitive to emotional stress. Given a stimulus such as embarrassment, the person's sympathetic nervous system will cause blood vessels to open wide, flooding the skin with blood and resulting in reddening of the face. In some people, the ears, neck and upper chest may also blush. As well as causing redness, blushing can sometimes make the affected area feel hot.