Herpes Simplex 1 & 2

Herpes simplex is often regarded as a sexually-transmitted infection, but it is not necessarily so. There are 2 types of herpes simplex virus (HSV): HSV type 1 and HSV type 2.

HSV-1 is associated with infection around the mouth and face region, and is also referred to as "oral herpes" or cold sores. It is estimated that about 50% of population in the US has been exposed to HSV-1. Whereas HSV-2 mainly cause infection around the genital area called "genital herpes", and it is sexually-transmitted.. Nevertheless, sometimes HSV-1 can cause genital infection and HSV-2 can cause oral infection. 

     HSV-1: Cold sores

The signs of HSV infection are painful blisters around the skin/mucosa surface of the mouth (oral herpes) or genitalia (genital herpes) which can last 1-2 weeks, often associated with fever. These blisters will break and become ulcers. About 80% of herpes simplex infection however, are asymptomatic (no signs and symptoms).

HSV is transmitted through contact with infected oral or genital secretion, either through kissing, touching, sharing towels, sexual activity etc. Most people are infected with HSV-1 during childhood by close skin contact with infected adults. HSV-2 is mainly transmitted through sexual act. HSV-2 can also spread from an infected mother to the new born during vaginal birth. 

Once a person first get the infection (primary infection), the virus will stay dormant in his/her body forever and it can't be cured. However, the dormant (sleeping) viruses do not cause any problem unless they are "activated". When the viruses are activated, they can spread to other people who come into close contact with the sufferer. The virus reactivation is referred to "recurrence" or "outbreak". The recurrence may or may not produce visible skin lesion thus the sufferer may not even know that he/she has a recurrence. Pain in the skin usually precedes the eruption of skin lesion.

     HSV-2: Genital herpes

The frequency of recurrence varies, sometimes once a month, sometimes once in a few years. Generally the recurrence will be less severe, less frequent with shorter duration over the time as our body get the antibody against it. That means the first or primary infection should be the most severe. HSV-2 causes more frequent recurrence (typically 4-6x a year) compared to HSV-1. Some factors which may trigger the recurrence are emotional stress, fever, illness, sunburn, trauma, surgery and menstruation.

Diagnosis of HSV infection is often made from the history and skin lesion. It can be confirmed by taking swab from the lesion for culture or viral DNA (PCR) test. 

When there is no symptoms or lesions, measuring antibody level (IgG & IgM) through blood test can be done. The presence of IgM means recent or current infection whereas IgG means previous or past infection. Once infected, IgG will only appear in the blood after 2-12 weeks and will persist for life. Thus, it is wise to repeat a negative IgG result after 8-12 weeks if the exposure is there. IgM cannot distinguish HSV-1 and HSV-2 accurately and may cross react with other viruses, thus giving false positive results. The glycoproteinG based antibody test can distinguish both types of virus. However, generally HSV antibody tests do not give very accurate results.

    HSV blisters / vesicles

The blisters caused by HSV can disappear by itself without any treatment. However, anti-viral treatment (oral or cream) may lessen the severity and duration of the signs and symptoms. The anti-viral (eg. acyclovir 400mg tds / 200mg 5x/day) is best given early at the first sign of recurrence or within the first 5 days, for a duration of 5-10 days. Some doctors suggest daily low dose anti-viral medicine (suppressive therapy eg. acyclovir 400mg bd) to reduce the frequency and severity of recurrence, especially for those with recurrence more than 6 times a year.

To reduce the risk of spreading to others, avoid close personal contact and sexual activity during recurrence. The problem is, sometimes recurrence may not produce any skin lesion and no one will be aware of it. Thus, it is advisable to always use condom during sexual intercourse to minimize the transmission of genital herpes. The risk cannot be eradicated totally even when using condom because skin around the genitalia not covered by condom may also spread the virus.

HSV infection cannot be cured but can be controlled or prevented. It is not life-threatening if you are infected with it, unless you are immunocompromised (extremely low immunity).