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Natural health & wellbeing, practical everyday life, Skincare

Fever blisters: causes and natural treatments

What is a cold sore?

What is a fever blister or cold sore?

Cold sores are recurrent infections caused by the herpes labialis virus (HSV-1).
The infection usually occurs in childhood, but mainly occurs in people with skin resistance or intolerance to the synthetic antiviral molecules most commonly used to combat HSV-1. Herpes labialis is a painful and unsightly disease that recurs with varying regularity on the lips.

Cold sores are usually mild and don’t lead to complications, except in people who are immunocompromised, in those with eczema, or in infants.

What are the symptoms of a cold sore?

The infection is most common in children between the ages of 1 and 4, but is usually asymptomatic. When symptoms do occur, they present as gingivostomatitis. This is an attack on the oral mucous membranes, causing vesicles - small blisters - to appear in the mouth and around the lips, which can extend as far as the chin. These vesicles will rupture and form ulcers. It’s accompanied by a high fever and large, swollen lymph nodes in the neck.

In adults, cold sores cause an itchy, tight feeling on a spot on the lip, sometimes accompanied by a headache and fatigue.
A cold sore is felt about 2 days before the vesicular eruption, and are usually accompanied by:

  • A feeling of heat or localised burning
  • Tingling
  • Itching

After a day or more, a cluster of vesicles may appear at the junction between the skin and the mucous membrane of the lip, nostril or chin. These become opaque quickly, break off and a scab forms. After 10 to 15 days, the scabs fall off without a trace.

If you are someone who suffers with recurrent outbreaks (about 20% of infected people), you can expect to develop blisters in the same place as your previous outbreak. Herpes labialis usually recurs 1-2 times a year.

What causes cold sores to appear?

Fever blisters on children

The first infection usually occurs in early childhood between the ages of 1 and 6, and often goes unnoticed. After infection, the virus remains dormant in nerve ganglia and can be triggered by various factors, including:

  • Stress
  • Fatigue
  • Anxiety
  • Lack of sleep
  • A cold or flu
  • A lowered immune system
  • An infection
  • Fever
  • Hormonal changes, such as menstruation
  • Exposure to the sun or cold
  • Use of corticosteroids and immunosuppressants
  • Surgery on the mouth

How long does a cold sore last?

Usually, you’ll feel an unusual sensation in your lip about a day before the sore appears. Once it’s visible, it’ll take between 7 to 10 days, on average, for it to heal. Depending on the case, it could take up to 15 days for the herpes to heal completely and leave no trace.

How to avoid catching the virus

Avoiding the spread of cold sores

Herpes labialis is a highly contagious disease, transmitted by direct contact with an infected person. Approximately 80% of adults are thought to have had contact with the virus in their lifetime, particularly during childhood. The cold sore is contagious until the scabs appear. Herpes can be transmitted to all uninfected people, especially young children.

Note that the herpes virus only survives for a few minutes in the open air, so it is only transmitted by direct contact with the lesions, or saliva. Unfortunately, there are periods of time when the virus is infectious, but secretions aren’t visible. During this time the virus can be passed on and nothing can be done to prevent it.

If you experience the warning symptoms, or the infection is visible:

  • Avoid close contact with other people, especially newborns, children with eczema, or people with immunodeficiency
  • Wash your hands after touching the lesion
  • Don’t share lip balms or lipsticks
  • Avoid contact sports such as judo or rugby
  • Avoid kissing
  • Avoid scratching the area, as this can carry the virus to the eyes or genitals
  • Avoid oral sex
  • Do not share towels

How to treat a cold sore

Remedies to treat fever blisters at any age

Cold sores are common and reoccur regularly. They can heal by themselves in just a few days. However, when applied at the very first sign of symptoms, essential oils can significantly limit their intensity, how long they last for, and reduce the risk of them coming back. Special mentions should be made for five essential oils: Tea Tree, Ravintsara and Linalool Thyme, which are powerful antiviral agents, Niaouli which stimulates the immune system and Peppermint which is a local anaesthetic.

Certain things should also be avoided to ensure that healing isn’t delayed. It’s important not to:

  • Rip off or damage the scabs of the sores while they’re healing
  • Apply make-up on top of the lesion to cover it
  • Disinfect the fever blister with an alcohol-based product
  • Take cortisone

Our natural recipes for treating a cold sore

Application of a pure essential oil:

Drying: Put 1 drop of pure Ravintsara essential oil on the cold sore 6-7 times a day until it heals. For adults only.


From 7 years of age

Recette réservée aux enfants de 7 ans et plus

Dilute 1 drop of Ceylon Cinnamon essential oil and 3 drops of Lemongrass essential oil in a teaspoon of St John's Wort vegetable oil. Apply, without massaging, a little of the mixture directly on to the cold sore 6 times a day, for 3 days, then 3 times a day, until it heals.


From 15 years of age
Recette réservée aux enfants de 15 ans et plus
Mix 1 drop of Rosemary Cineole essential oil diluted in 1 drop of Calophylla vegetable oil and 1 drop of St. John's Wort vegetable oil (or if sun exposure is a concern, use Hemp vegetable oil). Apply the mixture to the cold sore 5 times a day, at the first sign of a tingling sensation.
Mix 1 drop of Java Citronella essential oil and 1 drop of Niaouli essential oil in 3 drops of Hemp vegetable oil. Apply the mixture to the cold sore, 3 or 4 times a day.
Adults only
Recette réservée aux adultes

Dilute 1 drop of Ravintsara essential oil in 1 drop each of Calophylla and St. John's Wort vegetable oil (or if sun exposure is a concern, use Black Cumin vegetable oil) and apply to the lesion 5 times a day, until healed.


Disclaimer: This article is intended as a guide and is not intended to replace the advice of a physician, pharmacist, or other health care professional.
For any therapeutic use, consult a doctor or a pharmacist. Refer carefully to the contraindications and precautions for use of each essential oil. In case of doubt, consult a health professional.

Sources: Extracts from the books "Aromatherapia, tout sur les huiles essentielles" and "HUILES ESSENTIELLES, HUILES VÉGÉTALES & HYDROLATS : Mes indispensables", by Isabelle Pacchioni, published by Aroma Thera.

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