Water-filled blisters on and around the lips, caused by a common and highly contagious herpes simplex virus.
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At a glance
- Who it affects
- People with recurrent or first-time blisters around the lips.
- What you notice
- Tingling, itching, burning, then grouped water-filled blisters.
- What helps
- Antiviral treatment may be considered after examination; timing and severity vary.
What we do
A doctor may diagnose it from the appearance and discuss antiviral treatment. Recurrences vary.
What you can do
- Avoid touching the area.
- Do not share items that contact saliva.
- Seek help for severe symptoms.
Read the full page on Herpes labialis
What it is
Herpes labialis, also known as cold sores, is a common viral infection. It is caused by a DNA virus known as herpes simplex type 1. It presents as water-filled blisters on and around the lips. Other sites where it can occur are the gums, tongue, roof of the mouth, inside of the cheeks, the nose, or elsewhere on the body. At first it may just make the skin tingle, itch, sting or burn. It can occasionally cause fever, muscle pain and swollen lymph nodes.
After infection there can be two stages. In the primary infection, grouped blisters appear localised to one area, such as the lips and around them. The first episode is often severe, because the body does not yet have antibodies against the virus; the commonest triggers are fever and cold. Recurrences can then occur at intervals varying from weeks to months and are usually milder than the first episode. They are due to reactivation of the virus, often triggered by a cold, a cough, excessive sun exposure, fever, fatigue and hormonal changes such as menstruation.
How it spreads
Herpes can affect people of any age, including children. It spreads by touching infected saliva, mucous membrane or skin. The virus is highly contagious, and most people are affected by it before adulthood.
How we treat it
Herpes labialis is diagnosed by clinical examination by the doctor, from its typical appearance. Antibodies against the virus can also be detected in blood samples.
Mild cases are treated with an antiviral ointment applied to the area. In severe cases the doctor may prescribe an oral antiviral such as acyclovir or valacyclovir, usually for about a week. Frequent recurrences of cold sores may require longer-term treatment. Take whatever is prescribed exactly as your doctor directs.
Reviewed by Dr. D. A. Satish · date to be confirmedUnder clinical review
This page is being updated. The clinical information here comes from the clinic’s own patient leaflet and is under review by the doctor. Please ask at your consultation.
The information on this website is for general education only. It is not a substitute for a consultation, a diagnosis or a prescription. Always see a qualified doctor about your own condition.
This website is not for emergencies. If you have difficulty breathing, swelling of the lips, tongue or throat, or a sudden severe reaction, go to the nearest emergency department at once.