Herpes Simplex Virus (HSV)

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Images of Herpes Simplex Virus (HSV)


Herpes infections are caused by both herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2). Although HSV-1 more commonly causes sores in and around the mouth and HSV-2 more commonly causes genital and anal sores, both can appear anywhere on the body. Primary herpes is defined as the first outbreak of lesions and is usually more severe than future (recurrent) episodes.

Herpes simplex virus (HSV) is highly contagious and is easily transmitted through direct contact with the lesions of an infected person. However, the virus can also spread in the absence of symptoms or visible lesions. Affected individuals carry the virus in their bodies for the rest of their lives.

In newborn babies (within the first month of life), HSV infection, known as neonatal herpes, can potentially be life threatening, and symptoms almost always accompany infection. The virus is able to enter the brain and spinal fluid and can cause seizures and even death.

Who's at risk?

HSV infections in newborns are usually the result of the virus being passed from mother to baby at the time of delivery. The highest risk of passing herpes to a newborn occurs when a pregnant woman develops primary herpes during her third trimester. In contrast, the risk of transmitting herpes to a newborn is much less (about 3%) in women who have recurrent herpes during their pregnancy. Vaginal delivery also increases the risk of transmission if active lesions are present in the genital area at the time of delivery. Neonatal herpes (within the first month of life) can be very severe, affecting the brain and other internal organs. Even with treatment, newborns have a very high risk of death.

Infants can also become infected with HSV through direct skin-to-skin contact with someone who has an active lesion. For instance:

  • Kissing a child when you have an active lesion.
  • Changing a diaper if there is a lesion on your hand.
  • Breastfeeding with a lesion on the breast.
These infections are far less severe in nature and usually result in only sores on the mouth or lips of the infant.

Signs and Symptoms

Primary herpes is usually more severe than recurrent herpes. Both can cause painful blisters or ulcers on the lips or inside the mouth, but they may also cause similar lesions on other areas of the body, such as the face, hands, or genitals. Typically, 1–2 days before an outbreak, the skin where the lesions occur will have a burning or tingling sensation. Your child may also develop fever, swollen lymph nodes in the neck, irritability, poor appetite, and difficulty sleeping, especially with primary herpes.

Self-Care Guidelines

The goal of treatment is to make your child as comfortable as possible. Your child may have difficulty eating, drinking, and sleeping if he or she is in pain.

  • Encourage your child to drink as much fluid (milk, water, or juice) as possible to avoid dehydration.
  • Give over-the-counter acetaminophen (Tylenol®) or ibuprofen (Motrin®) for pain.
  • Avoid contact with other children – especially newborns or those with eczema or a weak immune system – until the sores are healed.

When to Seek Medical Care

Although children with mild recurrent herpes do not usually need any medical care, see your pediatrician if you think your child has primary herpes or if your child has recurrent herpes with more severe symptoms.

Treatments Your Physician May Prescribe

Your child's doctor may prescribe an antiviral medication to speed recovery of the sores. Acyclovir (Zovirax®) is the only antiviral medication that is available as a liquid and that is approved for use in infants.

Anesthetic mouthwashes or pain medication may also be given to reduce pain. If your child is unable to eat or drink because of mouth sores, he or she is at risk of becoming dehydrated. If this occurs, your doctor may recommend that your child receive IV (intravenous) fluids. 

Trusted Links

Clinical Information and Differential Diagnosis of Herpes Simplex Virus (HSV)


Bolognia, Jean L., ed. Dermatology, pp.1240-1241, 2028, 1236-1239. New York: Mosby, 2003.

Freedberg, Irwin M., ed. Fitzpatrick's Dermatology in General Medicine. 6th ed. pp.2059-2062, 2065, 2366, 2434-2437. New York: McGraw-Hill, 2003.

Kimberlin DW. Herpes simplex virus infections of the newborn. Semin Perinatol. 2007 Feb;31(1):19-25. 

Marques AR, Straus SE. Herpes Simplex. Wolff K, Goldsmith LA, Katz SI, Gilchrest BA, Paller AS, Leffell DJ, eds. Fitzpatrick's Dermatology in General Medicine. 7th ed. New York, NY: McGraw-Hill; 2008:1873-1884.