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Are Fever Blisters Contagious?

Yes, fever blisters are highly contagious. They are contagious right from the time they rupture until they are completely healed. You will find a few more important facts about this contagious infection in the following write up.
Rajib Singha
Last Updated: Jun 3, 2018
Fever blisters, also known as cold sores, are caused by a herpes infection. The herpes simplex virus type 1 (HSV-1) is responsible for causing these sores in most cases. There is another strain of the herpes simplex virus (HSV-2), which is mainly responsible for genital herpes (blisters develop on the genitals and surrounding areas). Although the HSV-2 can also trigger cold sores, in more than 95% of outbreaks, the HSV-1 is the main culprit. Note that, even the HSV-1 can cause an outbreak of sores in the genitals.
Fever blisters, can occur anywhere on the body, but mostly they develop on the lips, around the mouth, nose, cheeks or fingers.
How are Fever Blisters Transmitted
Fiver blisters are highly contagious. Close personal contacts, such as kissing, frequently spread the virus from one person to another; children are commonly infected in this way. Sharing items with a person with active blisters, may also spread the infection.
In 2 out of 10 adults with cold sores, the infection results from oral sex. This can happen if a person performs oral sex on another person who has genital herpes (HSV-2 infection). Cold sores occurring this way, however, do not have repeated outbreaks like they do in the case of the HSV-1 infection. Likewise, oral sex can also spread HSV-1 to the genitals.
The Most Contagious Period
Although cold sores are contagious from the time they rupture to the time of complete healing, they are the most contagious when they are oozing fluid. Sometimes, a person may not have any blisters, but he/she is still contagious and can pass the infection to others.
When Do Fever Blisters First Occur?
When a person contracts an HSV infection for the first time (primary infection), it is less likely that he/she will start showing any symptoms right away. When the virus enters the skin, it travels up a nerve and enters into dormancy. According to doctors, this hiding place might be located near the cheekbone. It may be sometime later that the virus may reactivate, and cause an outbreak of cold sores and other symptoms. Once the virus has entered the body, it stays there for life, and may keep causing occasional recurrences of cold sores.
Some people, however, do experience symptoms 3-5 days after an initial infection. Experts say that, fever blisters caused by the primary infection are more severe and stay longer than the ones caused by recurrent infections. As a person crosses the age of 35, he/she would start experiencing less recurrences of the blisters.
How to Sense An Outbreak
Most people who experience recurrent cold sores, experience a tingling, burning or itching sensation in the lip before the sores appear. The sensation may occur 1-3 days before an outbreak.
Triggers of Fever Blisters
There are several triggers that may break the dormancy of the virus and reactivate it. Common triggers include:
  • Stress
  • Illnesses
  • Injury to the area where the sores usually appear
  • Menstruation
  • Prolonged exposure to sunlight
  • Fever
Cure for Fever Blisters
The herpes simplex virus, once inside the body, cannot be eradicated. In other words, cold sores cannot be cured. The sores, however, clear up on their own within two weeks. Antiviral medicines can be used to reduce the pain and discomfort during an outbreak, and help symptoms resolve sooner.

Doctors advice patients to avoid spicy foods while they are still recovering. Applying ice to the sores helps reduce pain and irritation.

It is important to keep cold sores clean and dry, for they risk a secondary bacterial infection. Simply washing them with soap and clean water is good enough.
As fever blisters remain contagious until they clear up completely, adequate measures must be taken to keep them from spreading to others and elsewhere in the body, as well.

• The most important preventive measure is to wash your hands thoroughly with water and soap before and after touching your cold sores.

• A herpes infection of the genitals or the mouth is not as severe as when the same affects the eyes. It is called ocular herpes infection, and can cause blindness if left untreated. So, avoid touching your eyes after touching the sores.

• As an HSV-1 infection can also give you genital herpes, avoid touching the genital region after touching the sores.

• If you think you are going to experience a cold sore outbreak, then avoid kissing people, especially small children and newborn babies. Abstain from oral sex, as well.

• If you are otherwise healthy, then cold sores are less likely to cause any complications. But, this is not so with people with AIDS or other diseases that depress the immune system. So, if you are sick, then exercise extra precautions when you are around such people.
People whose fever blisters are triggered by sunlight, are recommended to use sunscreen products (SPF 15 or higher). Using a sunscreen can help prevent recurrence outbreaks of the infection, according to experts at the National Institute of Dental and Craniofacial Research.
Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.