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ConditionInfections

Human Herpesvirus 7 (HHV-7)

Human herpesvirus 7 (HHV-7) is a very common herpes virus that most people catch in early childhood, usually from the saliva of family members. Many infections cause no symptoms. When it does cause illness, it is usually a few days of high fever, sometimes followed by a pink rash as the fever breaks: a picture identical to roseola, which is more often caused by its close relative HHV-6. Febrile seizures can occur. Like other herpes viruses, HHV-7 stays in the body for life but rarely causes problems in healthy people.

Also called: HHV-7, human herpesvirus type 7, roseolovirus (with HHV-6)

By the iSymptom editorial team · Updated · 5 min read

At a glance

What it is
A herpes virus related to HHV-6 that infects most children by age 5.
How it spreads
Through saliva, often from parents or siblings who shed it without symptoms.
Illness
Often silent; can cause high fever for 3 to 5 days and a roseola-like rash.
Complications
Febrile seizures; rarely encephalitis; reactivation in transplant recipients.
Diagnosis
Usually clinical; blood PCR or antibody tests only in special situations.
Treatment
Supportive care for fever and fluids; no specific antiviral is routinely used.

When to get help

Call 911 or go to the ER

  • A seizure lasting more than 5 minutes, repeated seizures, or a child who does not wake normally afterward: call 911 or your local emergency number
  • Fever with a stiff neck, severe headache, confusion or a rash that does not fade when pressed
  • A baby who is limp, very hard to wake or struggling to breathe

See a doctor within a day or two

  • Any fever of 38 °C (100.4 °F) or higher in a baby under 3 months
  • A first febrile seizure, even if brief and the child has recovered
  • Fever lasting more than 5 days, or fever with signs of dehydration
  • Fever in a child or adult with a weakened immune system or a transplant

Book a routine appointment

  • A rash that lasts more than a week or is very itchy
  • A scaly oval rash on the trunk following a "herald patch" (possible pityriasis rosea)

Usually safe to manage at home

  • A child who had a few days of fever, is now fever-free with a pink rash and is eating, drinking and playing normally

About HHV-7

HHV-7 was identified in 1990. It belongs to the roseolovirus group with HHV-6, and both mainly infect a type of white blood cell called CD4 T-cells. Most children are infected between ages 2 and 5, typically a little later than HHV-6. By adulthood, nearly everyone carries the virus.

After the first infection, the virus remains dormant in the body and is shed intermittently in saliva throughout life. This is how it passes from adults to children.

Symptoms

Most HHV-7 infections cause no symptoms or a mild, unnoticed illness. When symptoms occur:

  • high fever, often 39 to 40 °C (102 to 104 °F), lasting 3 to 5 days
  • irritability, mild cold symptoms or diarrhea
  • swollen glands in the neck
  • a pink, flat or slightly raised rash on the trunk and neck that appears as the fever breaks and fades within 1 to 2 days, without itching

This pattern is called roseola (exanthem subitum or sixth disease). Most roseola is caused by HHV-6; HHV-7 causes a smaller share, and some children get roseola twice, once from each virus. See roseola.

Febrile seizures

High fevers from HHV-6 and HHV-7 are common triggers of febrile seizures in children aged 6 months to 5 years. A febrile seizure usually lasts less than 5 minutes, with stiffening and jerking of the limbs, followed by sleepiness. Simple febrile seizures do not cause brain damage, but a first seizure should always be assessed. See seizures.

What to do during a seizure:

  1. Place the child on their side on a safe surface.
  2. Do not put anything in the mouth or try to restrain movements.
  3. Time the seizure.
  4. Call 911 if it lasts more than 5 minutes, or the child has trouble breathing or does not recover.

Other conditions linked with HHV-7

  • Pityriasis rosea: a common rash with a single "herald patch" followed by smaller scaly oval patches on the trunk. Reactivation of HHV-6 and HHV-7 has been suggested as a cause, though the evidence is not conclusive.
  • Encephalitis: rare, reported mainly in young children and immunocompromised people.
  • Transplant recipients: reactivation of HHV-7, often with HHV-6 or cytomegalovirus, may contribute to complications.

Diagnosis

Testing is rarely needed in healthy children, because the illness is typical and resolves. When needed, for example in severe illness, encephalitis or transplant patients, doctors may use PCR blood or spinal fluid tests, or antibody tests. Because the virus persists in saliva and blood cells for life, a positive test does not always mean it is causing the current illness.

Doctors do check to rule out other causes of high fever in young children, such as urinary tract infections, ear infections and, if the child is very unwell, serious bacterial infections.

Treatment

There is no specific treatment for HHV-7 in healthy people. Care focuses on comfort:

  • Fever and discomfort: acetaminophen (paracetamol) or ibuprofen at the correct dose for age and weight, following the label. Do not give aspirin to children or teenagers. Fever medicines make children more comfortable but do not prevent febrile seizures.
  • Fluids: offer frequent drinks; watch for fewer wet diapers.
  • Rest and light clothing.
  • The rash needs no treatment.

In immunocompromised patients with serious disease, antiviral medicines used for related viruses may be considered by specialists.

Is it contagious?

Yes, through saliva, though most children catch it from adults who shed the virus without symptoms. Children are usually most contagious during the fever. By the time the rash appears, the child is generally well enough to return to child care once fever-free for 24 hours.

Frequently asked questions

What is human herpesvirus 7?

HHV-7 is a common herpes virus that most people catch in early childhood. It usually causes no symptoms, but can cause high fever and a roseola-type rash. Like other herpes viruses, it stays in the body for life, usually without causing further problems.

What is the difference between HHV-6 and HHV-7?

They are closely related and both can cause roseola. HHV-6 causes most roseola cases and is usually caught by age 2. HHV-7 is often caught slightly later and causes fewer recognized illnesses. Both can trigger febrile seizures.

Does HHV-7 cause pityriasis rosea?

Possibly. Reactivation of HHV-7 and HHV-6 has been found in some people with pityriasis rosea, and many experts think they play a role, but the link is not proven. Pityriasis rosea is not considered very contagious and usually clears on its own within 6 to 8 weeks.

Is HHV-7 dangerous?

In healthy children it is almost always harmless. The main concern is febrile seizures from high fever, which are frightening but rarely cause lasting harm. In people with weakened immune systems, such as transplant recipients, HHV-7 reactivation can contribute to complications.

Sources

This guide was written from current patient and clinical guidance, including:

  • American Academy of Pediatrics: Red Book, human herpesvirus 6 (including roseola) and 7
  • MedlinePlus: Roseola
  • Merck Manual Professional: Roseola infantum
  • American Academy of Family Physicians: Pityriasis rosea
  • CDC: Febrile seizures information (via NINDS)