Our complexion is not only determined by the amount of brown pigment (melanin) in our skin. Another major component is the color of blood. Just below the outermost layer of skin is a network of blood vessels that also contribute to skin color – actually it is the blood flowing through these vessels that are responsible for the redness of our skin under normal circumstances.
Naturally the skin appears more red than normal if there is larger amounts of blood flowing through these vessels. And less blood flow will reduce the redness and even contribute to a pale appearance. These blood vessels may widen (dilate) and narrow (constrict) for various reasons and this is how the blood flow in the area is either increased or decreased respectively.
Redness of the skin is more evident in lighter skinned people. The naturally brown colored skin pigment, melanin, can block most of the redness when more concentrated, like in darker skinned people. Just as pigmentation is genetically determined, so are the number of blood vessels that occur in the skin. Some people may have a more highly vascularized skin than others meaning that there are more blood vessels present. This also increases the redness of the face even with normal blood flow.
Why does skin turn red?
Redness of the face can occur for the same reasons as skin anywhere on the body. It is usually a consequence of two processes – vasodilation and inflammation.
Picture from Wikimedia Commons
The regulation of blood flow is controlled by two main factors – hormones and nerve impulses. This applies to any blood vessels. Hormones like epinephrine (adrenalin) and impulses carried by the tiny nerves in the blood vessel walls may cause an immediate change in the diameter of the blood vessels.
Very small muscle cells in the walls can contract to narrow the vessel (vasoconstriction) or relax to widen the vessel (vasodilation). Redness is due to vasodilation. It occurs when the tissues need more nutrients and oxygen, the body temperature is too high and as a secondary response to other events. In these cases it is not usually a disease process.
Sometimes it may occur suddenly, especially on the cheeks, and disappear just as rapidly. This is known as malar flushing.
Inflammation is a mechanism that is intended to protect the body against damage. It is a central process in most types of diseases. There are several changes that occur as a result of inflammation. Vasodilation is one of the events that occurs in inflammation. Apart from the redness that arises with vasodilation, there is also heat at the affected area. Swelling follows soon thereafter.
There are a host of possible causes of inflammation. When it comes to the skin of the face, it may occur with :
Our body uses the blood vessels in the skin as a cooling apparatus, similar to engine radiator fins. When the body temperature rises, the blood vessels dilate and heat is passed out into the environment. The increases blood flow and causes skin redness. Naturally the face tends to appear more red because it is usually the most exposed part of the body. Vasodilation in these cases is part of temperature control (thermoregulation). It can occur in any hot environment, like a busy kitchen, hot shower or sauna.
Strong emotions can alter the blood flow to any part of the body but it is the face that appears to be the most prone to this phenomenon. We know this as blushing and typically associate itwith embarrassment. However, anger, nervousness and other strong emotions can also cause a red face. In these instances it is the combination of hormones like epinephrine and nerve impulses from the brain that results in superficial vasodilation (widening of the blood vessels of the skin).
Alcohol and Spices
It is well known that a redness of the face may occur after a few drinks and a hot curry. The amount of alcohol or heat of the curry that may trigger skin redness varies from person to person. This reaction is usually short lived with eating spicy foods. However, it can persist for long periods after consuming alcohol. There is a danger of excessive heat loss as a consequence and one of the reasons why drinking alcohol excessively in cold weather can be dangerous.
Many cosmetics irritate the skin and cause inflammation. A red face is one of the consequences. Although cosmetics may be labeled hypoallergenic, it can still act as an irritant. This means that you are not allergic to the substances in the cosmetic application but it can nevertheless irritate the skin. Using heavily scented cosmetics or using make up for long periods of time everyday may be the cause of the irritation. It may not be evident immediately but with constant use, a red face becomes almost a permanent feature.
Picture from Dermatology Atlas Brazil
There are several skin diseases that can occur on the face. Most of these diseases are inflammatory conditions and redness is therefore a prominent feature, along with other symptoms like a rash and itchy skin. One condition that is known to cause severe redness of the face is rosacea. Apart from inflammation with rosacea, there is also an excessive number of blood vessels in the affected part of the skin. Acne, skin infections, malar erythema (seen in conditions like SLE) and irritant contact dermatitis are some of the other conditions where skin redness is prominent.
Sunburn is a consequence of prolonged exposure to sunlight. It is a common occurrence after spending a day out in the sun and may even arise with the overuse of tanning beds. The electromagnetic waves damage the skin and triggers inflammation thereby leading to redness. Human skin can tolerate sunlight for only so long before suburn occur. Sometimes mild sunburn can occur in the situations where it may seem unlikely. Sitting close to an open window on a sunny day or the reflection of light from snow or water can also cause sunburn. It may not seem as obvious and a little redness with a slight burning sensation of the skin may be all that is present.
A red face may occur as a symptom in a number or hormonal disturbances. It is seen in Cushing syndrome and hyperthyroidism where there is an excess of the cortisol and thyroid hormones respectively. Certain hormonal changes. particularly in women, may also cause redness of the face. It may not happen to every woman and is more likely to be prominent in lighter skinned individuals. Here the redness is not due to a problem and is often short lived in that it tends to resolve on its own without any treatment.