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Cold sores, sometimes called fever blisters, are caused by the herpes simplex virus (HSV). They're one of the most common oral conditions, with most cold sores developing on and around the lips.
There are two types of HSV:
It’s estimated that one-third of the world population has had at least one cold sore.1 Many people also have a herpes infection but no symptoms.
Cold sores are small blisters filled with fluid. They typically appear on and/or around your lips. You may have multiple sores at once.
Cold sores may appear swollen when they first form, but as the blisters erupt, they become shallow and begin to ooze. Then they begin to form scabs.
The entire process, from the earliest symptoms to complete healing, may take one to weeks. It’s usually divided into five stages:
Cold sores result from infection with herpes simplex virus type 1 (HSV-1). The infection is incurable, but it’s often asymptomatic. People of all ages and backgrounds can be affected by HSV-1.
People with HSV-1 may experience one or more cold sore outbreaks throughout their lives, but some never show symptoms. Outbreaks are often triggered by additional factors, such as:
A weakened immune system can also be a factor. Chemotherapy, organ transplant (anti-rejection) medication, and HIV/AIDS can all make outbreaks more likely.
Aside from the blisters themselves, cold sores can come with additional symptoms. These are especially common when a person is first infected and generally decrease with future outbreaks. They include:
Herpes simplex virus is contagious and can easily spread from person to person. It mainly spreads through saliva or contact with an infected person’s mouth. This means that all of the following can spread cold sores:
It’s best to avoid the above activities if you have an active cold sore. Otherwise, you’ll risk spreading the virus to the other person.
Even though HSV-1 isn’t usually associated with genital warts (unlike HSV-2), it can cause them if spread via oral sex.
Canker sores (or aphthous ulcers) are common oral lesions and are sometimes confused with cold sores. Here are some of the main differences:
Stress and other lifestyle factors can trigger cold sores and canker sores, but a virus ultimately causes cold sores. Canker sores aren’t a sign of a viral infection. However, H. pylori bacteria may be involved, as with stomach ulcers.
Cold sores aren’t always a major cause for concern, especially if you’ve had manageable outbreaks in the past.
However, you should visit your doctor if:
Your doctor can easily diagnose cold sores and recommend appropriate treatment.
Unfortunately, there is no permanent cure for cold sores. Herpes simplex is a lifelong infection. However, your doctor can prescribe medications and recommend home remedies to reduce discomfort and encourage healing.
While there’s no cure for the herpes simplex virus, you can treat cold sores and make outbreaks more manageable. Your doctor may prescribe an antiviral pill or topical cream to help reduce healing time.
Cold sore patches or a topical ointment like Abreva (docosanol) can also help cold sores heal faster. Your doctor may recommend pain medication or fever reducers as well.
Keep your lips moist as a cold sore heals to prevent cracking and bleeding. This will help promote healing.
If someone you know has a cold sore, it’s best to avoid the following until their symptoms have fully resolved:
If you have had cold sores in the past, you can’t guarantee that you won’t have another outbreak in the future.
However, keeping your immune system strong and avoiding known triggers may help. You can be proactive by eating a balanced diet, managing stress, and getting good sleep.
Cold sores themselves are unlikely to have severe complications. However, the virus that causes them can.
In rare cases, herpes simplex infection can affect the brain, eyes, or other organs. This can lead to various complications, including:
These complications are more common in people with weakened immune systems, such as those with HIV/AIDS. You should let your doctor know if you have persistent symptoms that affect areas other than your mouth (such as chronic fatigue, a headache, or fever).
Oral herpes is incurable but easily managed. Taking action early can relieve the symptoms and encourage healing if you have an occasional cold sore outbreak. In any case, cold sores in themselves aren’t life-threatening.
In addition, many people (possibly the majority of the world’s population) have HSV-1, and not all develop cold sores.
However, in rare cases, HSV-1 infection can spread to other parts of the body, leading to severe complications. Tell your doctor if you have a persistent headache, fever, or other symptoms.
Yes, cold sores are contagious. The virus that causes cold sores can easily spread to another person via an active sore, even if the other person never shows symptoms. The majority of HSV-1 infections have mild or no symptoms.
Kissing, oral sex, and sharing food or drinks can all cause the herpes simplex virus to spread. You should avoid these activities until you or the other person no longer have symptoms (even then, it’s possible to spread the virus).
Cold sores are very common, and the virus that causes them even more so. It’s estimated that about one-third of the world’s population has had a symptomatic oral herpes infection.
Cold sores usually last between one and two weeks. You should notice signs of healing after ten days. However, severe outbreaks can last longer, and new cold sores may appear while others heal.
Once you have herpes, cold sores can be triggered by various factors. Stress, overexposure to heat or cold, and a concurrent illness can all lead to an outbreak.
Generally, yes. Applying an ointment like Abreva or taking prescription antiviral medication can promote faster healing, especially if done early on.
Cold sores, or fever blisters, are caused by the herpes simplex virus (type 1 in most cases, but sometimes type 2). Most people worldwide have been infected with the herpes virus, but many never show symptoms.
Once you’re infected, cold sores can be brought on by stress, a weakened immune system, and other factors. Medication and home remedies can help speed up the healing process, but there’s no cure, so the sores may return.
Talk to your doctor if you have intense cold sore outbreaks or symptoms that affect your daily life, such as a fever or headache.
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