What is Herpes?

"Herpes," short for herpes simplex, is a common viral infection that often causes sores or blemishes on the skin, especially on the face or in the genital area.

Herpes simplex infection on the face is most common. Its symptoms are often known as "cold sores" or "fever blisters," which typically appear on the lips or mouth.

A fever blister due to HSV-1 click to enlarge

"Genital herpes," which occurs below the waist, sometimes causes sores of similar appearance, though its signs and symptoms can be quite varied.

The word "herpes" also can be used to describe a family of viruses (herpesviruses) that share certain traits. This family includes herpes simplex; varicella zoster virus (which causes "chickenpox"); Epstein-Barr virus (which causes "mononucleosis"); cytomegalovirus; and several others.

What does genital herpes mean?

Genital herpes is an infection caused by either of two viruses, called the herpes simplex virus type 1 or more commonly the herpes simplex virus type 2. These viruses are "ancient " living forms that infect most animal species. However, HSV-1 and HSV-2 are uniquely adapted to humans. The HSV-1 virus is the cause of cold sores or fever blisters. The HSV-2 virus is the major cause of genital herpes. The two viruses have many similarities, but it is their differences that are perhaps most important.

The two viruses look identical by the electron microscope. However, the proteins or spikes on the outside of the two viruses differ. As such, the body recognizes the two viruses differently, hence it makes antibodies to HSV-1 and these differ from antibodies to HSV-2. This distinction is central in allowing one to develop a "blood test" or serologic assay in medical jargon for the two viruses.

Another important distinction about herpes infections is that they are chronic. Once you have the infection it is lifelong. There are therapies, but no cures. Thus, genital herpes is a sexually transmitted infection one can acquire ten years previously, still have and pass on to someone else ten years after acquisition. Why is this important? Because it means you can get it from a long-standing monogamous relationship. Two people of thirty-five can be sole partners for two years and one can acquire genital herpes if one of these partners got genital herpes from another person years ago.

What does genital herpes usually look like?

Herpes can produce a wide range of signs and symptoms: Some are dramatic and fairly easy to recognize; some are subtle and may be ignored or confused with another ailment. In addition, herpes can be present as a "silent" infection -- causing no discernible signs or symptoms at all. Most people with herpes have symptoms so mild they don't realize they have it.

The most obvious signs of genital herpes are blister-like sores--much like the classic "cold sores"--that eventually crust over in a scab before healing. These can appear in various locations: the penis, scrotum, labia, vagina, upper thigh, buttocks, or around the anus.

recurrent herpes male click to enlarge

recurrent herpes female click to enlarge

buttock herpes click to enlarge

Herpes can also cause more subtle signs, for example: a red patch of skin, a tiny sore easily confused with a pimple or ingrown hair, a small slit (fissure) in the genital skin, or an irritation around the anus that might be confused with hemorrhoids. Herpes is not usually associated with vaginal discharge, but "the itching it produces" sometimes resembles yeast infections in women. It can also create small sores in and around the urethra that bring pain during urination.

Herpes "outbreaks" change over time

Herpes symptoms sometimes last longer or are more severe when a person experiences them for the first time, shortly after becoming infected. This is called a "first episode," and it tends to be more difficult because it's the first time one's immune system has had to contend with herpes type 1 or with type 2. First episodes can last as long as three or four weeks, and they sometimes involve a second outbreak of sores. Typically, first episodes also involve flu-like symptoms, including fever, swollen glands, and fatigue. And they can produce other non-genital signs and symptoms. Some, for example, result in headaches and sensitivity to light. These first episodes may also have a sore throat from simultaneous oral herpes. If one looks one can often see lots of small lesions on the external and internal genital region.

primary herpes male click to enlarge

primary herpes female click to enlarge

Since antiviral therapy for herpes exist and is quite effective for first episode infections, if you suspect you have a first episode, it's advisable to see a health care professional right away for an accurate diagnosis, appropriate treatment and counseling.

Why doesn't the virus eventually go away?

In a healthy individual, the immune system attacks herpes and resolves symptoms, but it can't completely rid the body of herpes. This is because the virus "hides" in a dormant state in some of our nerve root cells. Herpes evades the immune system by traveling the nerve pathways and hiding in nerve roots. When it does so, it enters an inactive or "latent" phase during which it appears to cause no symptoms and no harm.

The virus is dormant for life in these nerve roots, but intermittently it reactivates from dormancy. Certain triggers may cause this reactivation process. The virus to reproduces greater numbers of itself and travels the nerve pathways again, reaching the skin or certain mucous membranes in large enough quantities to be contagious. Sometimes there are visible signs of infection during these active periods, but sometimes there are none.

This cycle of latency and reactivation may be repeated hundreds of times but may follow dramatically different patterns from one individual to the next.

When is herpes active?

In many cases, herpes 's active periods are marked by signs and symptoms -- for example, the cold sores and other skin blemishes ("lesions") mentioned earlier. But not always. Herpes also can reactivate without causing any noticeable symptoms. Or it may cause mild signs or symptoms that are easily confused with something else.

Researchers measure reactivation with tests that look for the presence of viral particles on the skin or the mucous membranes, something called "viral shedding." And they have shown that viral shedding occurs almost always when signs and symptoms are present and sometimes when they're not. Viral shedding without signs and symptoms is often called "subclinical shedding," or "asymptomatic shedding." Studies have shown that this type of shedding may occur frequently. In some people five of every 100 days, in others 50 out of a 100 days. Whatever its frequency, it probably occurs sometimes in everyone who has herpes.

The chart below illustrates that people can asymptomatically shed virus either immediately before or immediately after a clinical recurrence of herpes. People can also shed virus between clinical recurrences at a time where there are no signs or symptoms of disease.

One clue to reactivation for many people is "prodrome," something they feel rather than see. Prodrome can involve an itching or tingling in the genital area, backache, shooting pains through the legs, or other sensations. It often serves as a warning that sores or other skin lesions are soon to come, but not always. In either case, the sensations of prodrome can be taken as a sign that herpes is in its active state.

One of the "bad news" features of herpes is that there are not tests that can determine of you are shedding or not on a particularly. There are, however, medicines that can be used to reduce shedding frequency.

How often will herpes reactivate?

This depends on a number of factors-for example, on whether you have herpes 1 or herpes 2.

Nearly all people with genital herpes caused by herpes type 2 will have reactivations that bring the return of signs and symptoms (these are called "recurrences" or "outbreaks"). For those with type 2 genital herpes, the average number of recurrences is slightly more than four per year. Virtually all people with type 2 genital herpes also will have periods of subclinical shedding.

People with genital herpes type 1, on the other hand, are less likely to suffer from symptomatic herpes recurrences, with an average recurrence rate of close to one per year. They apparently also suffer from fewer periods of subclinical shedding.

How often you reactivate also seems to depend partly on how recently you became infected. People tend to have more frequent recurrences and subclinical episodes in the first year after they become infected with genital herpes.

Overall, reactivation rates are highly individual, but those who have more severe symptoms also are more prone to subclinical or asymptomatic reactivation. On average, about one-third of all reactivations are "subclinical" -- that is, they don't cause sores or other visible skin blemishes.

Immunosuppressed patients reactivate HSV more frequently and for longer duration. This is one reason why antivirals are used commonly among such persons.

What triggers reactivation?

People who suffer from recurrent herpes naturally want to know what causes the virus to be active sometimes and latent at others. Medical science has yet to answer this question fully, though some triggers have been identified. In the case of oral herpes, research has shown that prolonged exposure to ultraviolet light (i.e., sunburn) frequently activates herpes in the face. Thus, sunscreen can be useful for preventing such reactivations. With genital herpes, some experiments suggest that excessive friction or injury to the genital area can cause herpes to come out of hiding. However there are little objective data indicating what really influences reactivation.

Individuals report a variety of triggers, including high stress, fatigue, and menstruation, but many others do not report such an association.