Cold sores are fluid-filled blisters that typically form on or near your lips. They usually clear up on their own within 10 days. Antiviral creams and medications can speed healing and relieve symptoms.
A cold sore, sometimes referred to as a fever blister, typically starts with a tingling, itchy, or stinging feeling on or near your lips and mouth. Over the next 48 hours, one or more fluid-filled blisters will appear.
Cold sores are contagious from the moment you first feel tingling to when they have completely healed. During this time, they can easily spread to other parts of your body and to other people through contact.
To help keep cold sores from spreading:
- wash your hands with warm water and soap after touching your cold sore
- don’t kiss anyone when you have a cold sore (especially babies)
- don’t engage in oral sex until your cold sore is completely healed, as you can give your partner genital herpes
Keep reading to learn more about cold sores, including their symptoms, appearance, causes, treatment, and prevention.
What’s the difference between a cold sore and a canker sore?
Cold sores and canker sores both cause pain and discomfort, but that’s where their similarities end.
- Canker sores are ulcers that form on the inside of the mouth, tongue, throat, and cheeks. They’re usually flat lesions. They’re not contagious and are not caused by the herpes simplex virus.
- Cold sores usually occur on the lips and outside the mouth. They’re highly contagious. Cold sores are raised and have a “bubbly” appearance.
The
According to the World Health Organization (WHO), an estimated
Many people with the HSV-1 infection have no symptoms or only mild symptoms. However, the infection can cause painful blisters that can recur over time.
Medications can relieve symptoms and speed healing time, but they can’t cure the infection.
You may notice a tingling or burning sensation near your lips several days before a cold sore develops. This is the best time to start treatment.
Once the sore forms, you’ll see a raised, red blister full of fluid. There may be more than one blister present, and they’re usually painful and tender to the touch.
A cold sore can last up to 2 weeks and is contagious until it completely heals. You may also experience one or more of the following symptoms during an outbreak:
Cold sores typically clear up on their own within 10 days, without treatment. However, you should make an appointment to see a doctor if:
- your cold sore has not healed with in 10 days
- you’re concerned that it may be something else (not a cold sore)
- the cold sore is large and very painful
- you also have swollen, painful gums, and sores inside your mouth
- you have a weakened immune system, due to chemotherapy, diabetes, or other health condition
- you have a red, painful, or swollen eye.
About herpes simplex eye infections
A herpes eye infection, caused by the same virus that causes cold sores, can cause a red, painful eye. It usually only affects one eye. Additional symptoms include:
- eye pain
- eye watering
- sensitivity to light
- blurred vision
- swollen eyelid
- blisters or rash on your eyelid or near your eye
If you have any of the above symptoms, see a medical professional promptly. It may not be serious, but it’s a good idea to have your eye examined and the cause diagnosed.
Without treatment, a herpes eye infection can affect your vision.
Cold sores are caused by the herpes simplex virus. There are two types of the herpes simplex virus:
- The herpes simplex type 1 virus (HSV-1) usually causes cold sores,
- The herpes simplex type 2 virus (HSV-2) usually causes genital herpes.
The sores caused by both forms of the virus are similar in appearance. It’s also possible for HSV-1 to cause sores on the genitals and for HSV-2 to cause sores on the mouth.
You can get the herpes simplex virus by coming in contact with people with the herpes simplex virus. This may happen through kissing, sharing cosmetics, or sharing food.
Cold sores are contagious when they’re visible, but can also spread when they’re not visible, in their early tingling and itching phase.
Oral sex may spread both cold sores and genital herpes.
Your first cold sore may not appear for up to 20 days after you’ve come into contact with the herpes simplex virus.
Once you get the herpes simplex virus, it can’t be cured. After your cold sores have healed, the virus remains dormant in your body. This means that new sores can appear at any time when the virus reactivates.
Some people with the virus report more frequent outbreaks when their immune systems are weak, such as during illness or times of stress.
The following conditions can cause a reactivation of the herpes simplex 1 virus:
- infection, fever, or a cold
- sun exposure
- stress
- HIV/AIDS or a weakened immune system
- menstruation
- surgery
- severe burns
- eczema
- chemotherapy
- dental work
Keep track of your individual triggers
Knowing what triggers your outbreaks can help prevent future outbreaks.
When you feel an outbreak coming on, think back to what may have triggered the reactivation. Were you prepping for an important school test or a work presentation? Did you just spend a day at the beach with a friend? Did you just have dental work?
Next time you’re facing a potential trigger, you can take preventive measures. This might include applying zinc oxide to your lips before spending time in the sun or practicing calming techniques if you’re feeling stressed or anxious.
If you’re experiencing frequent outbreaks, you can also talk with a doctor about
When you first contract the herpes simplex virus, it can cause more severe symptoms, as your body hasn’t built up a defense to the virus yet. These may include fever, muscle aches, and cold sores.
Complications are rare but can occur, especially in young children. Complications typically occur when the virus spreads to other areas of the body, such as your eyes or brain.
Make an appointment to see a doctor if you’re experiencing any of the following symptoms:
- high or persistent fever
- difficulty breathing or swallowing
- red, irritated eyes with or without discharge
Who’s at risk for complications from the herpes simplex 1 virus?
While there’s no cure for cold sores, some people with the herpes simplex virus rarely have outbreaks. When cold sores do develop, you have several treatment options.
Topical antiviral creams
You may be able to control pain and promote healing with topical antiviral creams.
These ointments, such as acyclovir cream (available as generic acyclovir or brand name Zovirax), tend to be most effective if they’re applied as soon as the first signs of a sore appear. Acyclovir cream should be applied 5 times daily for 4 days
Docosanol (Abreva) is another topical treatment option. It’s an over-the-counter cream that can shorten a cold sore outbreak by a few hours to a day. The cream should be applied five times a day until the sore is healed.
Oral antiviral medications
Cold sores can also be treated with oral antiviral medications, such as:
- acyclovir (Zovirax)
- valacyclovir (Valtrex)
- famciclovir (Famvir)
These medications are available by prescription only. Your doctor may recommend you take antiviral medications regularly if you’re experiencing complications with cold sores or if you have frequent outbreaks.
Oral antiviral medications for cold sores are best taken as soon as symptoms start. Medical literature suggests you start medication within 72 hours of symptom onset. This refers to the tingling sensation that precedes the appearance of blisters.
Home remedies
You may be able to relieve some of the symptoms of cold sores with these home remedies:
- apply ice or washcloths soaked in cold water to the blisters
- use lip balm that contains lemon extract
- take OTC anti-inflammatories (such as ibuprofen) to ease pain and swelling
- take lysine supplements, when taken on a regular basis, these supplements have been associated with fewer outbreaks for some people
- apply aloe vera gel or aloe vera lip balm to a cold sore 3 times a day.
- apply petroleum jelly such as Vaseline to your sore; it won’t necessarily heal a cold sore, but it may ease discomfort; plus, the jelly helps prevent cracking and serves as a protective barrier against outside irritants
- apply topical benzocaine, available over the counter without a prescription
Always apply creams, gels, or ointments to cold sores by dabbing, not rubbing, with your finger or a cotton swab. Be sure to wash your hands with soap and warm water before and after applying topical ointments.
If you have had cold sores before becoming pregnant, it’s pretty common to have an outbreak during pregnancy due to hormones and the changes your body is going through.
Cold sores during pregnancy do not usually affect your unborn baby. But talk with a doctor about your treatment options.
If you have a cold sore after your baby is born, you’ll want to take care not to kiss your baby or spread the virus to your baby through contact. Have a conversation with your doctor about how you can protect your baby from the virus.
Herpes simplex virus can cause health problems for babies, such as infections of the eyes or throat, or damage to their nerves.
You can help prevent the reactivation of the herpes virus by learning your triggers and taking the following steps:
- If you get cold sores when you’re in the sun, apply a zinc oxide lip balm to your lips before going outside.
- If a cold sore pops up each time you’re stressed, practice stress management techniques such as meditation and journaling.
- Drink plenty of fluids to avoid dehydration.
- Try not to touch your cold sore (apart from applying topical creams). If you do, wash your hands before and after applying.
- Consider replacing your toothbrush or cosmetic items (such as lipsticks or lip balms you may have used during the outbreak).
- Avoid kissing anyone who has a cold sore, and do not perform oral sex on anyone who has active genital herpes.
- Talk with a doctor if you’re experiencing frequent outbreaks; they can recommend medications that can suppress or limit virus reactivation.
To prevent spreading cold sores to other people
- wash your hands often
- avoid skin contact with others until your cold sore is completely healed
- don’t share items that touch your mouth, such as lip balm, food utensils, toothbrushes, or straws with others during an outbreak
- don’t kiss anyone until your cold sore is completely healed
- don’t have oral sex until your cold sore is completely healed