Genital Herpes in Pregnancy Health Article

Diagnosing and Classifying Genital Herpes

If you have herpes and become pregnant or if you are diagnosed with herpes for the first time during your pregnancy, your doctor classifies the type of infection you have to determine appropriate treatment.

How Is Genital Herpes Diagnosed?

Your doctor can identify your infection through a physical examination if you have the classic vesicles (small blisters)-multiple, grouped, and painful. But, if you are like many patients, you may not visit your doctor until the vesicles have evolved into ulcers (inflamed lesions) or crusted over.

There are several major concerns raised by a diagnosis of genital herpes. Even if you do have easily identifiable sores, the diagnosis should be confirmed by laboratory methods. Blood tests are available, which detect antibodies produced in response to HSV-1 or HSV-2. (Your body produces antibodies specific to organisms that invade the body; their job is to combat or kill these pathogens. If a blood test shows them present in your blood, it is evidence of current or past infection.) These tests can now differentiate between the two types of HSV: HSV-1, which is the more common cause of herpes labialis manifested by sores around the mouth and lips (commonly called "cold sores") and HSV-2, the more common cause of genital herpes. IgM antibodies to either of these two viruses indicate recent infection, but if you have IgG antibodies to either or both of the two viruses, it is impossible to tell when you acquired the infection or if the current outbreak is related to an active herpes infection. Therefore, more specific methods can be used to determine if the lesions are from herpes.

Cell Culture

A reliable diagnostic method involves taking a sample of the fluid from the base of a vesicle or ulcer and having it cultured (grown) in a laboratory. Usually, a culture result can be obtained within four days. If the virus is present, you have the infection. The older the active lesions are, the more difficult it may be to obtain a positive culture. This test is 100% specific for the actual virus being cultured (whether HSV-1 or HSV-2) and has fairly high yield on fresh specimens.

Smears

A test known as a Tzanck smear is a rapid method for identifying herpes infections. To perform this test, your doctor scrapes cells from a fresh ulcer or blister. These cells are spread on a glass slide, stained, and analyzed under a microscope. (A Papanicolaou smear (Pap smear) may also show evidence of herpes infection.)

Still, these smears have limitations: they cannot differentiate between HSV-1, HSV-2, and VZV (varicella-zoster, the chickenpox virus) infections. In addition, the smear test has a sensitivity of only 60 percent. So, in addition to a Tzanck smear, your doctor may also perform another diagnostic test, such as a viral culture or a polymerase chain reaction (PCR).

DNA Testing

PCR, a rapid test to detect HSV DNA, is one of the most accurate tests available. It involves taking a cell sample, isolating the cell's genetic material, and replicating it to make identification of the virus easier. This method has several advantages:

• results are available in a matter of hours and are at least as accurate as a cell culture;
• PCR is a more sensitive test. It can recognize infection for as long as the lesion is present. With a viral culture there are a larger number of false-negative results (people who have been infected but test negative when the lesion is old); and
• PCR can identify asymptomatic viral shedding of HSV.

Although PCR may be the future standard for diagnosing HSV infection, it is currently expensive and cumbersome and not used routinely in the diagnosis of oral and genital herpetic lesions. Its use at present is restricted to the diagnosis of HSV in the cerebrospinal fluid.

A Word about Patients with HIV.

In patients with HIV, cultures techniques are often used to make a definitive diagnosis of herpes simplex. The signs and symptoms of HSV infection may be altered in these patients, and it can be difficult to tell the difference between HSV infection and other causes of genital ulcers. Many infections can cause genital ulcers, and may be confused with HSV infection (including syphilis, chancroid, lymphogranuloma venereum, granuloma inguinale, Crohn's disease of the vulva, Behçet's disease, and trauma).

How Are Genital Herpes Infections Classified?

Genital HSV infections are designated as primary or recurrent infections.

• A primary infection occurs when IgG antibodies to both HSV-1 and HSV-2 are absent at the time a patient acquires genital HSV. (There may be a time lapse between when the infection develops and when IgG antibodies can be detected through a blood test.) However, IgM antibodies to the herpes simplex virus causing the infection most likely will be present at that point. Symptoms tend to be most severe in primary infections.
• Recurrent infections result from reactivation of genital HSV from a latent infection. (For example, the infection was "dormant" within nerve cells but has come out of latency and is currently causing symptoms.) The IgG antibodies against the offending virus are present at this point. This class of infection tends to be the least severe.

Many people infected with HSV have no symptoms during their initial infection. As a result, the first time you are diagnosed with HSV, it may represent either a primary or a recurrent infection.

What Are the Signs and Symptoms of a First-episode Infection?

In primary genital herpes, three to seven days after exposure, multiple vesicles (small blisters) appear on the skin in the genital region. In women, these lesions may occur on the vulva, urethra, vagina, cervix, or perineal area. The vesicles then open and form ulcers, which can be painful. It takes four to six weeks for these ulcers to heal. If the ulcers appear on the skin, they crust over before healing; if they appear on mucous membranes, they heal without crusting over. Ulcers do not leave scars.

Primary infections are often accompanied in the first few days by fever, headache, muscle aches, and malaise (not feeling well). Lymphadenopathy, a condition in which the lymph nodes in the groin become swollen and tender, may occur for the first three weeks of infection.

What Are the Signs and Symptoms of a Recurrent Infection?

Recurrent genital herpes occurs in patients already infected with HSV-2 (or, less commonly, HSV-1). In recurrent episodes, lesions are less likely to be accompanied by other "systemic" (body) symptoms. In addition, the lesions are fewer and tend to clear up in two weeks or less.