Penetrating Questions | Oh dear, what big red blotches you've got!

Jiná Ashline Columnist

My skin often looks red and blotchy immediately after I have sex. It doesn’t last too long, but for a while I thought it was an allergic reaction—to massage oil, lube, the laundry detergent I wash my sheets with, body lotion my partner uses, anything! After eliminating all of these things, I still get this rash. What’s wrong with me?!
—Flushed from more than the workout

Dear Flushed
Not to worry, there’s probably nothing wrong with you. It sounds like you have sex flush! Different physiological conditions cause flushing, a temporary reddening of the skin caused by any increase in blood flow, including sexual arousal. Sexual flush, also known as sex glow, is a common part of the sexual response cycle whether you are with a partner or alone, and is more evident in some people than in others.

Sex flush is a rosy, reddish rash that appears on the body late in the excitement phase of the sexual response cycle. Remember vasocongestion? If you read “Come, on honey—if you don’t it’ll hurt!” in the 3.27.08 issue on blue balls, you’d be familiar with the term. Vasocongestion refers to a swelling of body tissues that is caused by an increase in both blood flow and blood pressure in and around those tissues. In this case, sex flush is a result of vasocongestion of the skin. It occurs more often in women than men and is more noticeable in lighter skin tones. Sex flush is generally more apparent in warmer conditions and may not appear in cooler climates.

Noticing your own sex flush or that of your partner may be of interest because the degree of the flush varies based on the level of arousal that a person is experiencing. Some sources suggest that the degree of the sex flush can be used as a marker to predict the intensity of orgasm that will follow.

Women who experience sex flush will most often notice pinkish spots develop on the breasts and abdomen, which will then spread to the rest of the chest, face, hands, soles of the feet and possibly over the entire body. In an often less-noticed location, vasocongestion is also responsible for the darkening of the clitoris and the walls of the vagina during this stage of sexual arousal.

Sex flush in males has a less consistent pattern than in females. In men it typically starts on the upper abdomen, spreads across the chest, then continues to the neck, face, forehead, back and sometimes the shoulders and forearms.

Sex flush tends to begin in the early stages of sexual activity, during the excitement phase, the first of four phases that make up the sexual response cycle that the human body goes through from the first feeling of arousal until after orgasm.

This model, developed by sex researchers William Masters and Virginia Johnson, divides the typical sexual response cycle of humans into four phases: excitement, plateau, orgasm and resolution. These stages correspond with the level of arousal that the body is experiencing and occurs whether you are having sex with a partner or pleasuring yourself.

The signs of sexual excitement that people are best able to recognize are erections of the penis or clitoris and the appearance of lubrication, but those are not the only important changes happening! Masters and Johnson discovered that during the cycle, two other major physiological changes occur—an increase in blood flow (vasocongestion) and muscle tension in specific parts of the body.

The cycle starts with vague sexual feelings that develop into a physical sexual excitement, the first phase. This phase is usually part of foreplay. As humans get sexually excited, they experience an increase in heart rate and blood pressure, and a noticeable sex flush often appears. There is also an increase in muscle tension throughout the body, and some people experience nipple erection.

Next is the plateau phase, marked by more intense sexual excitement that includes increased heart rate and blood pressure, spreading sex flush, increased breast size, heavy breathing and muscular tension. This phase is like a commitment to the experience, because all of these responses prepare the body for orgasm.

Not surprisingly, orgasm, the release of all of the built-up sexual tension throughout the body, is the third phase. All of the physiological responses peak in this phase, quickly followed by a release of muscular tension and a return to a normal resting state of the body, where normal levels of heart rate, blood pressure, breathing and muscle contraction return.

This return to the resting state is the fourth phase, the resolution phase. Swollen body parts diminish, sex flush disappears and the muscles relax. This phase can vary in length for different people, but is generally longer for women than men.

As mentioned, sex flush may occur as early as the first phase of excitement and persist throughout the remainder of the cycle. The sex flush typically disappears soon after orgasm occurs, fading in reverse of the way it appeared. Because the resolution time is different for different people, depending on their bodies and the intensity of their orgasm, it may take up to two hours or more. Sometimes intense sweating will occur as the body returns its functions to their resting states.

It’s great that you looked at potential sources of your reaction to rule them out as causes. If your flush is itchy, lasts for many hours or days, or if you feel concerned about it for any reason, it’s always worth visiting your doctor to rule out any allergic reactions or sexually transmitted infections (STIs).

Some STIs and allergies may manifest themselves in similar ways to sex flush and it is possible to confuse them. If your flush seems irregular in any way, visit a doctor to eliminate other potential factors.

Take advantage of your new knowledge of sex flush and have fun trying to decipher your and your partner’s experience. A darker and more widespread sex flush may be a good indication that you or your partner is about to have an amazing orgasm, so embrace your sex flush and the information it reveals. Expand upon and vary your foreplay activities and notice if the intensity of your flush changes.

Happy sexing!

—Jiná Ashline ’08 is a religion major with a women’s studies correlate. She is also president of C.H.O.I.C.E. Each week she will answer a question about sex and sexuality. Send your questions to jiashline@vassar.edu or by dropping a note in Box 2172.