Fever blisters, commonly known as cold sores, present as tiny, fluid-filled blisters on lips, under the nose, or around the chin. There is no difference between cold sores and fever blisters, simply different terms for the same virus. Learn more about the symptoms, what causes cold sore recurrence, and how to manage and prevent transmission.
What Are Cold Sores and Fever Blisters?
Medically Reviewed By Colgate Global Scientific Communications
What is a cold sore? Fever blisters, commonly known as cold sores, present as tiny, fluid-filled blisters on lips, under the nose, or around the chin. There is no difference between cold sores and fever blisters, merely different terms for the same virus. According to the American Dental Association (ADA), these blisters are brought on by a contagious and common virus known as herpes simplex virus type 1 (HSV-1) and is passed from person to person by saliva or by skin contact. While lip sores should heal without leaving a scar, there’s no cure for HSV-1 so the blisters may return. Learn more about the symptoms, what causes cold sore recurrence, and how to manage and prevent transmission.
What are the symptoms and stages of healing?
Fever blisters usually pass through multiple stages as noted by Mayo Clinic:
Stage 1: Many people feel an itching, burning or tingling sensation around their lips for a day or so before small, hard, painful lesions appear, and blisters erupt.
Stage 2: Small fluid-filled blisters typically break out along the border where the outside edge of the lips meets the skin of the face. Cold sores can also occur around the nose or on the cheeks.
Stage 3: The small blisters may merge and then burst, leaving shallow open sores that will ooze fluid and then crust over. Cold sores usually crust within four days and heal completely within 8 to 10 days.
HSV-1 is what causes fever blisters, and unfortunately, once you have them, you’re likely to find cold sores on lips again. Recurrences typically appear at the same spot each time and tend to be less severe than the first outbreak. The symptoms of your first outbreak of fever blisters may also come with additional issues such as:
- Painful swelling
- Open sores in the mouth
- Sore throat
What triggers a recurrence of cold sores?
There are multiple reasons cold sores reoccur after the initial contraction and outbreak. After your first infection the virus remains inactive in the nerves of the face. Then, a trigger occurs to activate the virus, and cold sores reappear. Possible triggers include:
- After a period of illness
- Stress (mental and emotional)
- Sunlight exposure
- Changes in your immune system
Cold sores in the mouth can appear if you have a weakened immune system or other existing medical problems. Cold sores can also appear for no known reason.
How do you get cold sores?
According to the Mayo Clinic, cold sores are most contagious when oozing blisters are present. However, it’s important to remember that you can still transmit HSV-1 to others even when you’re not showing signs or symptoms. Here are some helpful tips to avoid passing on the HSV-1 virus or coming into contact with it:
- Avoid skin-to-skin contact with others while blisters are present.
- Avoid sharing items that have come into contact with your saliva like utensils or lip balm.
- Keep your hands clean.
- Prevent an initial HSV-1 infection in children by preventing anyone from kissing them who has signs of fever blisters.
Your doctor may prescribe an antiviral medication if you frequently develop cold sores or if you’re at a high-risk for complications due to a weakened immune system. Sunblock is also useful if sunlight triggers a recurrence.
To help avoid future cold sores, it's essential to replace your toothbrush after the cold sore goes away. The virus that caused your cold sore can live on your toothbrush for days, and if you brush your teeth with this contaminated toothbrush, your lip could become re-infected. To avoid a hasty repeat of your outbreak, discard your old one.
Are cold sores herpes?
According to the Mayo Clinic, herpes simplex virus (HSV-1) is the cause of cold sores. The virus that causes genital herpes (HSV-2) is different, but both viruses can affect your mouth or genital area and can be spread by oral sex.
Fever Blister Treatment
How fast can you heal cold sores? Generally, cold sores clear up in two to four weeks. You may be able to speed the healing process up with oral antiviral medication, creams, and injections. These drugs cannot get rid of the virus and only work in advance of a cold sore appearing. Once the fever blisters appear, you’ll have to wait for them to heal. However, if you have a weakened immune system, HSV-1 can cause severe illness.
Cold sores are common and inconvenient, which can be frustrating for patients. The good news is that by taking a few precautions and staying mindful of what triggers cause an outbreak, you can deal with this issue quickly and do your best to avoid passing the virus on.
This article is intended to promote understanding of and knowledge about general oral health topics. It is not intended to be a substitute for professional advice, diagnosis or treatment. Always seek the advice of your dentist or other qualified healthcare provider with any questions you may have regarding a medical condition or treatment.