MSD Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Herpes Simplex Virus Infections


The Manual's Editorial Staff

Reviewed/Revised Feb 2024
Get the full details
Topic Resources

What are herpes simplex virus (HSV) infections?

Herpes simplex is a viral infection Overview of Viral Infections A virus is a microorganism, a tiny living organism. Other common microorganisms include bacteria. Viruses are much smaller than bacteria and can be seen only with the most powerful microscopes... read more that causes a rash of small, painful blisters that turn into open sores. The sores go away, but the virus stays in your body for the rest of your life. The virus can become active again and cause more sores.

What causes HSV infection?

There are 2 types of herpes simplex virus. Both are spread by physical contact with an infected person.

Herpes simplex virus spreads very easily, including through:

  • Touching

  • Kissing

  • Having sex

  • Sharing things such as towels or razors with an infected person

You're more likely to get herpes from someone if they have sores. However, infected people can sometimes spread the virus when they don't have sores.

If you're pregnant and have herpes in or around your vagina, you may give the infection to your baby during birth even if you don't have sores.

What are the symptoms of HSV infection?

Most people have either:

  • Oral herpes, which affects your lips or inside your mouth


  • Genital herpes, which affects your genitals, including the penis, the skin outside the vagina, or the inside of the vagina

Oral herpes

Symptoms of a first infection include:

  • Many painful sores in your mouth, which last 10 to 14 days and can hurt so much you don’t want to eat or drink

  • Sometimes, a fever, headache, or body aches

When the virus becomes active again:

  • First, you'll feel itching, burning, or tingling on your lip

  • Then, one or more sores will form at the edge of your lip, usually in the same spot with each outbreak

  • The sore will quickly form a crusty scab that falls off after about 8 to 12 days

The lip sore is sometimes called a “cold sore” or “fever blister” because it’s often triggered by colds or fevers.

Genital herpes

Symptoms of a first infection include:

  • Many painful sores in and around your vagina, penis, or anus

  • In women, the sores are sometimes inside the vagina—these are usually less painful than sores outside of the vagina

  • Fever or feeling sick

  • Burning when you pee

  • Trouble peeing or passing stool

When the virus becomes active again, you may have:

  • Tingling, itching, or aching around your vagina or penis

  • Within a few days, painful blisters in these areas

The blisters usually go away after a week. If you get sick easily or have a weak immune system, Overview of the Immune System The immune system is your body's defense system. It helps protect you from illness and infection. The immune system's job is to attack things that don’t belong in your body, including: Germs... read more you’ll get sores that grow bigger and take weeks to heal. See your doctor as soon as you can.

Herpes in other areas

Newborns who got infected with herpes during birth (neonatal herpes simplex Herpes Simplex Virus (HSV) Infection in Newborns Herpes simplex virus infection usually causes only annoying, recurring blisters in healthy adults but can cause severe infection in newborns. Newborns may become infected at birth or after birth... read more Herpes Simplex Virus (HSV) Infection in Newborns ) usually get sick before they're 4 weeks old. They may have sores all over their body. Sometimes the virus infects their brain, causing seizures, coma, and death. Herpes in newborns is dangerous and life-threatening. Even with treatment, many babies die.

How can doctors tell if I have HSV infection?

Doctors can usually tell if you have an HSV infection, including oral herpes or genital herpes, based on your symptoms. To tell for sure, they may:

  • Send fluid from a sore to a lab for testing

  • Do blood tests

How do doctors treat HSV infection?

Doctors can't cure HSV infection, but antiviral medicine can help your symptoms go away faster.

  • Antiviral medicines work best when you take them at the first sign of tingling or discomfort, before blisters appear

  • If you get painful sores often, doctors may have you take prescription antiviral medicine every day (suppressive therapy)

  • If your eye is infected, an eye doctor (ophthalmologist) will give you antiviral eye drops

To help you feel better, doctors may suggest you:

  • Use an anesthetic cream or ointment to help your sores feel better

  • Take pain medicine (for example, acetaminophen or ibuprofen) if your sores really hurt

  • Wash the area gently with soap and water

  • Put ice on your sores

How can I prevent spreading oral or genital herpes?

To prevent spreading oral herpes, if you have tingling or a cold sore:

  • Don’t share a drinking glass

  • Don’t kiss people or have oral sex

  • Don’t let someone touch your sore

To avoid getting or spreading genital herpes:

However, because herpes may infect genital areas that aren't covered by a condom, condoms don't completely protect you.

Remember that you may still be able to spread herpes to other people, even if you don't have symptoms.

quiz link

Test your knowledge

Take a Quiz!