Herpes Simplex Infections

Alternate Names : Fever Blister, COLD Sore

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: