Herpes Simplex Virus (HSV)

HSV-1 vs HSV-2

Either type can infect either site. Testing that identifies the type helps predict how often genital herpes will recur.

How herpes spreads

HSV spreads through direct contact with infected skin or saliva:

• kissing, sharing utensils or lip balm (mainly HSV-1)
• vaginal, anal or oral sex
• from mother to baby during birth (neonatal herpes, rare but serious)
• from a cold sore to the fingers (herpetic whitlow) or eyes

The virus spreads most easily when sores are present, but it is also shed from normal-looking skin, which is how most genital herpes is transmitted. Herpes does not spread through toilet seats, towels or swimming pools in any meaningful way.

Symptoms

First (primary) infection

Many people have no symptoms or mild ones they do not notice. When symptoms occur, usually 2 to 12 days after exposure, they can be severe:

• clusters of small, painful, fluid-filled blisters that burst into shallow ulcers and crust over
• fever, aches and swollen lymph nodes
• oral: in young children, widespread mouth and gum sores (herpetic gingivostomatitis)
• genital: sores on the vulva, vagina, cervix, penis, buttocks or anus, with burning urination and sometimes trouble passing urine
• healing in 2 to 4 weeks

Recurrent outbreaks

• tingling, itching or burning (prodrome) 1 to 2 days before blisters appear
• fewer, smaller sores in the same general area
• healing in 5 to 10 days
• triggers: stress, illness, fever, sunlight, menstruation, friction, and a weakened immune system

Forms of herpes simplex infection

• Cold sores: blisters on or around the lips
• Genital herpes
• Herpes keratitis: infection of the cornea, a leading infectious cause of corneal blindness if untreated
• Herpetic whitlow: painful blisters on a finger
• Herpes gladiatorum: skin infection spread in contact sports such as wrestling
• Eczema herpeticum: widespread infection in people with eczema, needs urgent treatment
• Herpes encephalitis: rare but serious brain infection, usually HSV-1
• Neonatal herpes: infection of a newborn, can affect skin, eyes, mouth, brain and organs
• Herpes esophagitis and severe infections in people with weakened immune systems

Diagnosis

• Swab PCR test from a fresh blister or sore: the most accurate test, and it identifies HSV-1 or HSV-2
• Type-specific blood tests (antibodies) show past infection when no sores are present, but they can give false results and are not recommended for routine screening of people without symptoms
• Eye exam with special dye for suspected keratitis
• Lumbar puncture and MRI for suspected encephalitis

Treatment

There is no cure, but antivirals work well.

Antiviral medicines

• Acyclovir, valacyclovir and famciclovir are the main options.
• First episode: a 7 to 10 day course reduces severity and duration.
• Episodic treatment: taken at the first tingle of a recurrence, shortens it by about 1 to 2 days.
• Suppressive therapy: daily medicine reduces recurrences by 70 to 80 in 100 and lowers the risk of passing genital herpes to a partner by about half.
• IV acyclovir in hospital for encephalitis, neonatal herpes and severe infections.
• Eye infections are treated by an eye doctor with antiviral drops, gels or tablets.

Symptom relief

• acetaminophen (paracetamol) or ibuprofen, following the label dose
• salt-water baths and loose cotton clothing for genital sores
• pouring water over the area while urinating, or urinating in a warm bath, if it stings
• petroleum jelly or numbing cream on sores
• for cold sores, over-the-counter docosanol cream started early may shorten them slightly

Herpes and pregnancy

The greatest risk to a baby is when the mother first acquires genital herpes late in pregnancy. Tell your obstetric provider if you or your partner have herpes. Daily antiviral medicine is offered from 36 weeks to reduce outbreaks at delivery, and a cesarean birth is recommended if there are genital sores or prodromal symptoms when labor starts.

Prevention

• avoid kissing and oral sex when cold sores are present
• avoid sex during genital outbreaks and prodromal symptoms
• use condoms, which reduce but do not eliminate risk
• consider suppressive therapy if your partner does not have herpes
• do not kiss newborns if you have a cold sore
• wash hands after touching sores and avoid touching your eyes
• use lip sunscreen if sunlight triggers cold sores

Living with herpes

A herpes diagnosis can cause distress, but it is common and manageable. Recurrences usually become less frequent and milder over time. With honest communication, condoms and suppressive therapy, many couples where one partner has herpes never transmit it. Having genital sores also raises the risk of acquiring HIV, so regular STI testing is recommended for people with new partners.

Frequently asked questions

What is the difference between HSV-1 and HSV-2?

HSV-1 usually causes cold sores on the mouth but can also cause genital herpes, often through oral sex. HSV-2 mainly causes genital herpes and tends to recur more often. Both cause similar blisters and are treated with the same antiviral medicines.

How is herpes spread?

Herpes spreads through direct skin-to-skin contact, kissing, and vaginal, anal or oral sex. It can spread even when no sores are visible, through asymptomatic shedding. It is most contagious when blisters or sores are present.

Can herpes be cured?

No. The virus stays in nerve cells for life. Antiviral medicines control outbreaks, reduce how often they happen, and lower the chance of passing herpes to a partner. Outbreaks usually become less frequent over time.

What does a herpes outbreak look like?

It starts with tingling or burning, then small clusters of fluid-filled blisters appear on red skin. They burst into painful shallow sores, then crust and heal within 1 to 2 weeks without scarring. First outbreaks are usually more severe.

Can I have herpes without symptoms?

Yes. Most people with HSV-1 or HSV-2 do not know they have it because symptoms are absent or very mild. They can still pass the virus on through asymptomatic shedding.