Overview, Causes, & Risk Factors

Herpes simplex infections are caused by a herpes simplex virus. This virus is most likely to attack the skin and nervous system. The infection is temporary, usually lasting 1 to 3 weeks. It causes small, irritating, and often painful blisters on the skin and mucous membranes. These blisters become fluid-filled and eventually crust over as healing starts. They are most often found on or around the mouth and nose, the eyes, and in the genital region.

What is going on in the body?

Humans are the only known source of herpes simplex viruses. The infection is spread by close physical contact and can be passed from mother to infant during pregnancy or childbirth. The infection is chronic and can reactivate throughout life.

This type of infection is caused by two types of herpes simplex virus. Herpes simplex virus-1, also called HSV-1, is an infection that tends to appear in the facial area, most often around the nose and mouth. Herpes simplex virus-2, also called HSV-2, tends to appear in the genital region. HSV-2 infections are usually spread sexually. Symptoms of infection with HSV include burning, itching, tingling, and pain at the site of infection, along with blisters filled with fluid. The affected individual may also have a low fever and enlarged lymph nodes in the neck.

Most people first get HSV-1 during childhood. It causes blisters around the mouth and nose. Although the infection clears up within 2 to 3 weeks, the inactive virus remains in the body forever. Reactivation of HSV-1 later in life often causes cold sores in the same areas.

Adults or young adults generally contract HSV-2 through sexual contact. HSV-2 causes painful ulcers in the genital region. Sometimes HSV-2 infection is associated with mild cases of meningitis, which is an inflammation of the brain and spinal cord. For both HSV-1 and HSV-2, reactivation takes the form of single ulcers at the site of the original infection.

The eyes can also be a site of HSV infection. Eye infections can vary in severity. The person should get treatment for them as soon as possible to avoid complications. An HSV infection can also occur on the finger. This is called a herpetic whitlow, and it often results from touching an ulcer at some other site.

Infants can acquire HSV-1 or HSV-2 from their mothers during pregnancy or childbirth. This usually happens when the mother has HSV for the first time. HSV infection in newborn babies is a serious matter. It can result in the death of the infant or brain damage even when the infant is treated appropriately. Infection in someone with a weakened or damaged immune system can also be severe and may require prolonged treatment.

Many outbreaks occur without any obvious reason. However, the following factors may trigger a recurrence:

What are the causes and risks of the infection?

Causes of this infection include:

People in the following categories may be more at risk for herpes simplex infection:

Symptoms & Signs

What are the signs and symptoms of the condition?

Someone with an active herpes infection may have the following symptoms:

Diagnosis & Tests

How is the infection diagnosed?

A doctor can take a swab of the infected secretions from the mouth, nose, or genital sores. Then he or she sends it to a lab where techs test it for HSV. This is called a culture, and HSV can be detected rapidly in infected specimens by using special stains. The doctor will also evaluate the person's symptoms and ask about recent exposure to someone who has or had a herpes simplex infection.

Prevention & Expectations

What can be done to prevent the infection?

The herpes simplex virus can be passed from person to person. Someone with oral herpes should not share lipstick, utensils, or drinks with others. Touching and kissing can also spread the virus. Someone with genital herpes should use condoms during sexual activity to help prevent the spread of the infection. People who have immune system problems or who have frequent recurrences often take antiviral drugs, such as acyclovir and valacyclovir, to help prevent reactivation. A doctor who specializes in the condition should monitor a pregnancy complicated by HSV infection.

What are the long-term effects of the infection?

Most infections clear up in 3 weeks or less. But the infection is chronic because the virus stays in the body forever. So, it may come back over and over throughout the rest of the individual's life. Infection in newborn babies and people whose immune systems are not working well can result in brain damage or death.

What are the risks to others?

Herpes infections are highly contagious and can be passed from one person to another much like a cold or the flu. Good hand washing, wearing gloves, and avoiding direct contact can all help prevent the spread to others.

Treatment & Monitoring

What are the treatments for the infection?

In most cases, herpes simplex blisters on the face are self-limiting. They will usually crust over and go away in about 2 weeks. If they last longer, a doctor should be consulted. Treatment for oral herpes includes the following:

Acyclovir is used to treat HSV in newborn babies and people with genital herpes who have faulty immune systems. Acyclovir or its relative, valacyclovir, can also be used to treat HSV in otherwise healthy people. Other treatment is aimed at preventing secondary infection and relieving symptoms.

What are the side effects of the treatments?

Antiviral medicines may cause nausea, vomiting, diarrhea, and allergic reactions. Creams and ointments may cause an allergic reaction in some individuals.

What happens after treatment for the infection?

Some people will have frequent recurrences of HSV. They sometimes benefit from taking acyclovir as a preventive measure.

How is the condition monitored?

Any new or worsening symptoms should be reported to a healthcare provider.