There are many causes of facial flushing, some which should receive medical attention and others that naturally occur and offer no harm. Facial flushing can be a simple reaction to diet, such as having eaten spicy food or taken in too much alcohol, or it can accompany menopause or a high fever, notes the Cleveland Clinic.
One of your skin's major contributions to your health involves thermoregulation. When your body's core overheats, the hypothalamus region of your brain sends a message to your blood vessels to dilate. During those times, warm blood moves from the internal organs to the blood vessels in the skin's surface. According to Mayo Clinic, this response "substantially increases the transfer of heat from the core to the periphery." In short, blood vessels move body heat to the surface of your skin, where it can dissipate.
This reaction, called vasodilation, causes your skin to flush, a symptom most obvious on your face due to a variety of factors. Facial skin has a high number of blood vessels on the surface, plus the facial skin is thinner than on other body parts, making the underlying vessels more apparent. The structure of the vessels themselves is also different in your face, allowing flushing to become prominent.
Many people experience the effects of facial flushing, often called blushing, at times of embarrassment. During embarrassing situations, your body releases adrenaline, a natural stimulant. The adrenaline causes your pupils to dilate in order to see more, slows digestion so your muscles receive the bulk of your body's energy and speeds breathing and heart rate in order to increase oxygen levels in the body. This last effect causes vasodilation, which appears as a flush on your skin.
Ray Crozier, a psychology professor at the University of East Anglia in the U.K., pointed out that blushing is a uniquely human response. He theorizes that it developed as a way to fend off a possible retaliatory response from another. As a social signal, flushing lets others know that we understand we have committed a social mistake. Crozier further points out that while there are other reasons for facial flushing, such as responses to sexual arousal or alcohol consumption, those responses result from stimulants other than increased adrenaline flow.
A number of diseases include facial flushing as a symptom. In rosacea, a chronic inflammatory skin condition, flushing is the major symptom. Rosacea sufferers often have a history of flushing before the disease progresses to include other symptoms such as broken blood vessels and red, blister-like papules, according to the Cleveland Clinic.
The Mayo Clinic includes flushing as a major symptom of Cushing's syndrome. The syndrome develops as a result of high levels of the hormone cortisol in the body over long periods of time. Many commonly used corticosteroids such as prednisone can increase the body's level of cortisol, and therefore flushing, although the body naturally produces the hormone as well.