Some medical causes of a flushed face are extreme emotional states, rosacea and high fever, according to Healthline. Hormonal changes, such as those involved in hot flashes and pregnancy; ingestion of niacin; and taking drugs used to treat erectile dysfunction are also some causes of flushing, claims Healthgrades.
Skin flushing is a feeling of warmth and rapid reddening of the neck, upper chest or face. It occurs as a result of increased blood flow, which causes the blood vessels to enlarge, giving the skin a flushed appearance. Flushing is rarely a medical concern, but it may indicate a serious medical condition, such as Cushing's disease or a niacin overdose, according to Healthline.