Educational Content: This article is for informational purposes only and does not constitute medical advice. Always consult a healthcare provider for diagnosis and treatment.
Definition of Herpes Simplex Type 1 (HSV-1)
Medically reviewed by Dr. Otari Nergadze, Neurosurgeon | Updated: January 2026
Herpes simplex type 1 is a herpes virus that causes cold sores and fever blisters in and around the mouth.
In rare cases, when someone's immune system is severely compromised, this virus can cause infection of the brain (encephalitis), requiring intravenous therapy.
Herpes simplex type 1 is also known as herpes simplex virus type 1 (HSV-1) human herpesvirus 1 (HHV-1).