Cold sores are small, painful blisters that typically form on or near the lips. These tiny fluid-filled blisters are sometimes called fever blisters or oral herpes, notes the Mayo Clinic. (1)
Cold sores are highly contagious and can spread through saliva or skin contact. It’s a common condition, with some people experiencing their first outbreak during childhood, according to TeensHealth. (2)
There's no cure for cold sores, but the good news is that many cold sores usually go away on their own in a week or two and don’t leave a trace. (1)
To relieve pain and accelerate healing, medications and home remedies can help, says the Mayo Clinic. (3)
Signs and Symptoms of Cold Sores
Symptoms of cold sores vary, with the first exposure or primary outbreak usually being the most severe, says?Allison Arthur, MD, a board-certified dermatologist based in Orlando, Florida.
According to the American Academy of Dermatology, first-time cold sore symptoms may include:?(4)
- Painful blisters on the lips, cheeks, mouth, nose, or throat (which eventually pop and form scabs)
- Mouth and throat pain
- Swelling in the neck
- Fever and body aches
You’ll still have painful blisters with recurrent outbreaks, but the more severe symptoms, like body aches and a fever, are less likely to return.
It’s important to note that while cold sores typically form outside of the mouth, these sores?can?form inside the mouth during your first outbreak. This is known as acute herpetic gingivostomatitis. (4) For this reason, you might initially mistake a first-time cold sore for a canker sore.?Canker sores are ulcers that form on the mucous membranes inside the mouth or on the tongue, per the Mayo Clinic. (5)
A cold sore can develop anytime after you're first infected with a herpes simplex virus (HSV). You may also notice early signs of an outbreak one or two days before a blister appears.
Early symptoms of a cold sore may include: (4)
The blister appears within 24 to 48 hours of the first symptom. After a couple of days, the blister will burst and ooze with pus. A scab will then form over the blister. (4)
Common Questions & Answers
Cold Sore vs. Canker Sore: What’s the Difference?
You may mistake a cold sore for a canker sore, but these bumps have key differences, including their:
Appearance Canker sores are painful red or white bumps that typically form on the gums, inside the lips or cheek, or on the tongue. Unlike cold sores, they don't blister or scab.
Contagiousness Unlike cold sores, canker sores aren't caused by herpes and they aren't contagious. So while it is possible to spread a cold sore to someone through kissing or sharing eating utensils, this isn’t the case with a canker sore. (5)
Cause Cold sores are commonly caused by HSV-1, and yet the cause of a canker sore is unknown. Factors that may contribute to a canker sore include a family history of canker sores, injury to the mouth, a weak immune system, or a?vitamin deficiency. (5)
Causes and Risk Factors of Cold Sores
Cold sores are caused by the herpes simplex virus (HSV). (1)
There are two types of HSV. Most cold sores are caused by type 1 (HSV-1). Type 2 (HSV-2) usually affects the genital area, but it can also cause cold sores around the mouth, says Dr. Arthur. (2)
This can happen after oral sex with someone who has genital herpes, or if you kiss someone who has HSV-2 cold sores around their mouth.
Upward of 90 percent of adults have the virus that causes a cold sore, and these individuals are often infected in childhood after being kissed by someone with the virus. (1)
Cold sores can be found on or around the lips, but some people also get sores on the cheek, or around the nose and the eyes. (1)
Once you’re infected with HSV-1, the virus travels to your nerves and stays in your body for life. The virus can lie inactive or dormant, so some people infected with HSV-1 never get a cold sore. In fact, some people don’t even know that they’re infected with the virus because they never have symptoms. (4)
Unfortunately, you can still pass the virus to others even when you don’t have visible symptoms of a cold sore, according to NHS Inform. (6)
Cold sores occur when the virus awakens in the body.
Certain factors can trigger this awakening and cause an outbreak, notes the AAD. (7)
These triggers include:
- A viral infection or fever
- Exposure to sun and wind
- Changes in the immune system
Sometimes, a cold sore has unknown triggers.
How Are Cold Sores Diagnosed?
A cold sore is treatable at home, so most people don’t see a doctor. Under certain conditions, however, a severe cold sore may require a visit to your family doctor or a dermatologist. (3)
Doctors can usually diagnose a cold sore by looking at the lesion. More rarely, your doctor may take a fluid sample from the cold sore to see if you have HSV. (3)
Prognosis of Cold Sores
There's no cure for cold sores, nor is there a cure for the virus that causes a cold sore. (1) Once you're infected, the virus stays in your body for life.
But even with recurrence, in healthy individuals the prognosis for a cold sore is typically good and complications are rare, unless you are immunocompromised.
Duration of Cold Sores
A first-time cold sore typically lasts 10 to 14 days. Later outbreaks might last this long, or they might heal sooner, as soon as within five days. (4)
Treatment and Medication Options for Cold Sores
A number of treatments are helpful for cold sore outbreaks.
Because cold sores are caused by a virus, the first line of defense is the over-the-counter antiviral Abreva (docosanol)?to help your body fight the virus and reduce the duration of an outbreak. (3) This medication is most effective when taken at the first sign of tingling and itching. (6)
Additionally, use an over-the-counter oral pain reliever, such as lidocaine,?benzocaine (Orajel),?dibucaine, or?benzyl alcohol,?to relieve cold sore pain and inflammation. (3) Apply ointments and creams directly to the cold sore as directed. Other pain relief options include a cool compress, or take?ibuprofen (Advil),?aspirin, or?acetaminophen (Tylenol). (2,3)
If a cold sore doesn’t respond to over-the-counter treatment, ask your doctor about a prescription antiviral to shorten the duration of an outbreak. If you have frequent outbreaks, you may need an antiviral daily to suppress the virus and control symptoms. (8) You can also ask about the topical therapy Denavir (penciclovir), which can be used to shorten the duration of a cold sore outbreak, according to Medline Plus. (9)?To use, you typically apply it every two hours while awake, for four days.
Alternative and Complementary Therapies
Other tips to reduce an outbreak include getting plenty of rest, managing?stress, and wearing sunscreen to protect against strong sun exposure. (7)
Alternative therapies may also relieve a cold sore, though more research is needed. According to a past study, researchers found that a combination of rhubarb and sage had the same healing effect as acyclovir, a topical antiviral commonly used to treat herpes infections. (10)
Additionally, research published in 2018 in Integrative Medicine found that 3 percent propolis ointment applied to areas affected by HSV-1 reduced symptoms of infection by three to four days. Propolis is a compound produced by bees. Participants applied the ointment four to five times a day for 10 days. (11)
Prevention of Cold Sores
Cold sores are highly contagious, but you can protect yourself. Since the virus can spread through close personal contact, it's important that you don't share personal items with anyone — especially during an outbreak, notes the Cleveland Clinic. (12)
Personal items include clothes, makeup, razors, and towels. You should also avoid sharing food and drinks with others.
Keep in mind, too, cold sores can spread to other parts of the body. So if you have an outbreak, avoid touching your cold sore with your hands. After applying creams or ointments over a cold sore, wash your hands immediately with warm soap and water. (1)
If you're prone to cold sores in the summer, sunlight might be a trigger. Wear a moisturizing lip balm with SPF protection to help prevent an outbreak. (7)
Complications of Cold Sores
See a doctor if you have cold sore complications. This includes a cold sore that spreads to different parts of your body, such as your eyes or fingers. Additionally, see a doctor if you have a weak immune system. (2)
“People who are immunocompromised?[have a weakened immune system due to HIV or medications following organ transplantation] can develop severe outbreaks and have frequent episodes of cold sores,” says Arthur.
If your body is unable to fight the virus, it can also spread to your spinal cord and brain. (1) If you have eczema, there's also the risk of cold sores spreading across your body. (1)
Research and Statistics: Who Has Cold Sores?
It's estimated that over half of Americans between ages 14 and 49 have the virus that causes cold sores. Many people get the virus in childhood after being kissed by an infected person. (7)
Some people with the virus never have an outbreak, whereas others have frequent outbreaks throughout their life. Fortunately, cold sores occur less often with age. Outbreaks tend to slow down after the age of 35. (7)
Related Conditions and Causes of Cold Sores
Cold sores have been associated with other conditions and health problems. For example, if you have a weakened immune system, certain illnesses might trigger an outbreak. These illnesses include: (12)
Skin conditions like eczema and psoriasis also put you at risk of an outbreak. And because fluctuating?hormone levels can trigger outbreaks, a cold sore might develop while you’re pregnant or menstruating. (12)
Resources We Love
Favorite Resources for Essential Cold Sore Information
American Academy of Dermatology (AAD)
The AAD provides a comprehensive overview of cold sores ranging from symptoms to self-care. There's an information section for parents, as well as information on public health programs. Use the “find a dermatology” tool to locate a doctor in your area.
This is another helpful tool to find useful information related to cold sores. The Cleveland Clinic doesn’t only offer advice on treatments, but also advice on prevention and living with cold sores. Use the online tool to chat with a representative or schedule an appointment.
For more on connecting with a dermatologist online, check out our article “Why You Shouldn’t Skip Your Dermatology Appointment During COVID-19.”
The Mayo Clinic provides straightforward information about cold sores. The site features general information such as symptoms, treatments, and prevention. You’ll also find guidelines on when to see a doctor, and tips on how to prepare for an appointment.
MedlinePlus offers a wealth of resources for cold sores. You’ll find general information for symptoms and treatments, as well as links to clinical trials, journal articles, and patient handouts.
Favorite Online Support Network
Support groups are an excellent way to get advice and connect with those who understand your condition. Join the Drugs.com support group to ask questions and find the latest information related to oral herpes.
Editorial Sources and Fact-Checking
- Cold Sores: Overview.?Mayo Clinic. June 17, 2020.
- Cold Sores.?TeensHealth. February 2019.
- Cold Sores: Diagnosis.?Mayo Clinic. June 17, 2020.
- Cold Sores: Signs and Symptoms.?American Academy of Dermatology.
- Canker Sore: Overview.?Mayo Clinic. April 3, 2018.
- Cold Sores.?NHS Inform. May 20, 2020.
- Cold Sores: Who Gets and Causes.?American Academy of Dermatology.
- Cold Sores: Diagnosis, Treatment, and Outcome.?American Academy of Dermatology.
- Penciclovir Cream. Medline Plus. December 15, 2017.
- Saller R, Buechi S, Meyrat R, Schmidhauser C. Combined Herbal Preparation of Topical Treatment of Herpes Labialis.?Forsch Komplementarmed Klass Naturheilkd. December 2001.
- Rossi M, Jacobs B. Herpes Simples Virus. Integrative Medicine. 2018.
- Cold Sores Prevention. Cleveland Clinic. September 12, 2019.