Herpes encephalitis

By Medically reviewed by hellodoktor


What is herpes encephalitis?

Herpes encephalitis is an inflammation of the brain tissue. It is frequently caused by viral infections. However, in some rare cases, bacterial infections can engender encephalitis. There are two major types of encephalitis: primary and secondary. Primary encephalitis occurs when a virus directly infects the brain and spinal cord. Secondary encephalitis occurs when an infection starts elsewhere in the body and then travels to your brain.

It is noticed that herpes encephalitis is a rare but serious disease that can be life-threatening. You should call your doctor immediately if you have any signs or symptoms of encephalitis.

How common is herpes encephalitis?

This condition is estimated to affect at least 1 in 500,000 individuals per year and some studies suggest an incidence rate of 5.9 cases per 100,000 live births.

Please discuss with your doctor for further information.


What are the symptoms of herpes encephalitis?

It is found that most people with viral encephalitis have either no symptoms or mild flu-like symptoms, such as the following:

  • Headache
  • Fever
  • Aches in muscles or joints
  • Fatigue or weakness

More-serious cases require prompt medical care. Additional signs and symptoms of more serious encephalitis may include the following:

  • Confusion, agitation or hallucinations
  • Seizures
  • Loss of sensation or paralysis in certain areas of the face or body
  • Muscle weakness
  • Double vision
  • Perception of foul smells, such as burned meat or rotten eggs
  • Problems with speech or hearing
  • Loss of consciousness

Some signs and symptoms in infants and young children may also include:

  • Bulging in the soft spots (fontanels) of the skull in infants
  • Nausea and vomiting
  • Body stiffness
  • Inconsolable crying
  • Poor feeding or not waking for a feeding
  • Irritability

When should I see my doctor?

If you have any signs or symptoms listed above or have any questions, please consulting with your doctor. Everyone’s body acts differently. It is always best to discuss with your doctor what is best for your situation.


What causes herpes encephalitis?

There are a great number of causes of this condition. Some common causes of encephalitis may include:

Herpes simplex virus

There are two types of herpes simplex virus (HSV). Either type can cause encephalitis. HSV type 1 (HSV-1) is usually in charge of cold sores or fever blisters around your mouth, and HSV type 2 (HSV-2) commonly causes genital herpes. Encephalitis caused by HSV-1 is rare, but it has the potential to cause significant brain damage or death.

Other herpes viruses

Other herpes viruses that may cause encephalitis include the Epstein-Barr virus, which commonly causes infectious mononucleosis, and the varicella-zoster virus, which commonly causes chickenpox and shingles.


These viruses include the poliovirus and the coxsackievirus, which usually cause an illness with flu-like symptoms, eye inflammation and abdominal pain.

Mosquito-borne viruses

Arboviruses, or arthropod-borne viruses, are transmitted by mosquitoes or other blood-sucking insects. Mosquito-borne viruses can cause infections that include West Nile, La Crosse, St. Louis, western equine and eastern equine encephalitis. Symptoms of an infection may appear within a few days to a couple of weeks after exposure to an arbovirus.

Tick-borne viruses

The Powassan virus is a well-known tick-transmitted virus that causes encephalitis in the U.S. and Canada. Symptoms usually appear about a week after exposure to the virus.

Rabies virus

Infection with the rabies virus, which is usually transmitted by a bite from an infected animal, causes a rapid progression to encephalitis once symptoms begin. Rabies is a rare cause of encephalitis in the U.S.

Childhood infections

Common childhood infections — such as measles (rubeola), mumps and German measles (rubella) — used to be fairly common causes of secondary encephalitis.

Risk factors

What increases my risk for herpes encephalitis?

There are many risk factors for herpes encephalitis, such as:


Some types of encephalitis are more prevalent or more severe in certain age groups. In general, young children and older adults are at greater risk of most types of viral encephalitis. Encephalitis from the herpes simplex virus tends to be more common in people 20 to 40 years of age.

Weakened immune system

People who have HIV/AIDS, take immune-suppressing drugs, or have another condition causing a compromised or weakened immune system are at increased risk of encephalitis.

Geographic regions

Mosquito-borne or tick-borne viruses are common in particular geographic regions.

Season of the year

Mosquito- and tick-borne diseases tend to be more prevalent in spring, summer and early fall in many areas.

Diagnosis & treatment

The information provided is not a substitute for any medical advice. ALWAYS consult with your doctor for more information.

How is herpes encephalitis diagnosed?

If your doctor suspects that you may experience this condition, a physical examination will be performed and some tests will be also recommended by your doctor. Some common tests may include:

Brain imaging

Brain imaging is often the first test if symptoms and patient history suggest the possibility of encephalitis.

CT-scan and MRI

MRI can produce detailed cross-sectional and 3-D images of the brain and CT-scan can produce cross-sectional images.

Spinal tap (lumbar puncture)

With a spinal tap, the doctor inserts a needle into the lower back to extract cerebrospinal fluid (CSF), the protective fluid that surrounds the brain and spinal column. Changes in this fluid can indicate infection and inflammation in the brain.

Other lab tests

Samples of blood or urine, or of excretions from the back of the throat can be tested for viruses or other infectious agents.

Electroencephalogram (EEG)

Your doctor may order an EEG, a test in which a series of electrodes are affixed to the scalp. The EEG records the electrical activity of the brain. Certain abnormal patterns in this activity may be consistent with a diagnosis of encephalitis.

How is herpes encephalitis treated?

Anti-viral medications play a role in treating herpes encephalitis. However, they aren’t effective in treating other forms of encephalitis. Instead, treatment often focuses on relieving symptoms. These treatments may include:

  • Rest
  • Pain killers
  • Corticosteroids (to reduce brain inflammation)
  • Mechanical ventilation (to help with breathing)
  • Lukewarm sponge baths
  • Anticonvulsants (to prevent or stop seizures)
  • Sedatives (for restlessness, aggressiveness, and irritability)
  • Fluids (sometimes through an IV)

You may need to be hospitalized during treatment, especially with brain swelling and seizures.

Lifestyle changes & home remedies

What are some lifestyle changes or home remedies that can help me manage herpes encephalitis?

The following lifestyles and home remedies might help you cope with herpes encephalitis:

  • Practice good hygiene. Wash hands frequently and thoroughly with soap and water, particularly after using the toilet and before and after meals.
  • Don’t share utensils.Don’t share tableware and beverages.
  • Teach your children good habits. Teach your children to practice good hygiene and to avoid sharing utensils at home and school.
  • Get vaccinations. Keep your own and your children’s vaccinations current. Before traveling, talk to your doctor about recommended vaccinations for different destinations.

If you have any questions, please consult with your doctor to better understand the best solution for you.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Review Date: August 16, 2017 | Last Modified: September 12, 2019