Herpes encephalitis is a rapidly progressing disease that accounts for around 10 percent of the encephalitis cases. It results in fatal and sporadic encephalitis in America. The clinical presentation in this condition includes aseptic meningitis, fever along with other rapidly progressing conditions that may involve altered consciousness.

Herpes encephalitis occurs because of the herpes simplex type 1 or type 2 viruses. The cases that are caused by the herpes simplex type 1 virus are seen to affect individuals below the age of 20 and above the age of 40. The type 1 virus causes blisters in the area surrounding the mouth and these blisters are also called cold sores or fever blisters.

As many as 30% of the herpes encephalitis cases are caused due to an initial herpes simplex virus infection. Most of the cases may also be caused following a reactivation of an infection that occurred at an earlier time. The herpes encephalitis condition that is caused due to the type 1 virus can be transmitted by way of contact with a person who is infected.

The symptoms of herpes encephalitis include fever and headache that can last for around 5 days. The fever in these cases is quite often followed by seizures, partial paralysis, hallucinations, changes in personality and behavioral changes along with alteration in consciousness levels. Brain damage may be observed in these cases among adults as well as children. Such brain damage is observed in the frontal lobes as well as temporal lobes and this damage can be severe.

Among newborn children herpes encephalitis symptoms may include irritability. Lethargy, seizures, tremors along with poor feeding developing between the periods of 4 to 11 days after the delivery may also be observed. The prognosis for this condition is not great and many cases of this condition are fatal. Herpes encephalitis is quite rare with an incidence of only around 3 cases for every 100,000 people every year.

If this condition is left untreated then the mortality rate can be as high as 70 percent. With early treatment around 40% of the patients can recover without major neurological defects. There is no documented and proven racial predisposition for this condition. Likewise no specific sex predisposition is also observed for this condition.