Infections
Cold sores
Cold sores are small, fluid-filled blisters on or near the lips, usually caused by the herpes simplex virus type 1 (HSV-1). Very many adults carry this virus.
Reviewed by Raashid Haque, MD, board-certified dermatologist
For education only. This guide does not diagnose or treat any condition.
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Sun can trigger cold sore flares in some people, and SPF lip balm is a practical preventive step.
Look for
- SPF 30 or higher
- Broad spectrum on the label
- Water resistant (40 or 80 minutes) if you swim or sweat
Full details, cautions and sourcesAvoid
- Balms with no SPF listed
- Strong menthol, camphor, or cinnamon flavors if your lips sting or peel
These are products Dr. Haque has reviewed and recommends for different reasons. Unless a product is clearly marked 'Affiliate link,' it is not one. Most are not.
Food and lifestyle may play a part in Cold sores too
Anti-inflammatory eating and lifestyleLearn about Cold sores
Cold sores (also called fever blisters or herpes labialis) are caused mostly by herpes simplex virus type 1, or HSV-1. Many people pick up the virus in childhood, often from a kiss or shared food or drinks from a family member, and often never know it. After the first infection, the virus stays in nerve cells in the face. It can wake up later and cause a cold sore. Some people have many outbreaks and some have few or none.
How it often looks. Many people feel tingling, itching, or burning at the spot first. Then small, clustered blisters appear, usually on the edge of the lip. They break open, ooze, and form a crust. On lighter skin the area often looks red or pink. On brown and Black skin it may look darker brown, purplish, or only slightly red, so the tingling and the blisters themselves can be the best clues. After healing, some people notice lighter or darker marks where outbreaks keep returning.
Course. A first outbreak can last 2 to 3 weeks. Later outbreaks are often milder and many heal within about 1 to 2 weeks.
Contagious? Yes. The virus spreads most easily when a blister is present, but it can also spread when there are no sores or symptoms at all. Many people with HSV-1 never get a visible cold sore.
What it is not. A canker sore (aphthous ulcer) is a different problem. It happens inside the mouth and is not contagious. A cold sore is also not a sign of poor hygiene. Having HSV-1 is common and nothing to be ashamed of.
Self-care
What it is
Keeping the sore clean and dry, not picking at it, washing hands after touching it, and avoiding kissing and sharing items until it has fully healed.
Often considered when
At any outbreak, alongside or instead of medicine. Cool compresses and a hydrocolloid patch are common comfort and cover-up options.
Less suitable or needs caution when
Not a substitute for care if you have red-flag signs such as eye symptoms or a weak immune system.
What to watch for
Touching the sore and then the eyes or other skin can spread the virus. Cracking or bleeding means slower healing.
How long to judge it
Most outbreaks improve within 1 to 2 weeks.
Questions to ask
- How can I tell when I am no longer contagious?
- Is a patch a good option for me?
Over the counter
What it is
Over-the-counter pain relievers and numbing or protective lip products that may ease soreness.
Often considered when
The sore is painful or uncomfortable, especially when eating or speaking.
Less suitable or needs caution when
Allergy to an ingredient, or a history of reactions to numbing products. Check with a clinician or pharmacist about pain medicines if you are pregnant, or if you have kidney, stomach, or liver conditions.
What to watch for
Stinging, new redness, or itching from a product, which may mean irritation or allergy.
How long to judge it
Comfort measures work as needed. They do not shorten the outbreak.
Questions to ask
- Which pain relief is safest for me?
- Should I avoid any lip products during an outbreak?
What it is
A non-prescription cream, sold in the United States, that is made for cold sores and that some people use at the first sign of tingling.
Often considered when
Someone gets early warning signs and prefers a non-prescription option for occasional outbreaks.
Less suitable or needs caution when
Known allergy to the ingredients. Not meant for use inside the mouth or near the eyes. Ask a clinician about use in young children.
What to watch for
Mild skin irritation, dryness, or headache. Studies suggest the benefit is modest, perhaps shortening an outbreak by about a day.
How long to judge it
Judged over the course of one outbreak.
Questions to ask
- Is an OTC cream enough for my pattern of outbreaks?
- What should I do if it is not helping?
Prescription creams and gels
What it is
Topical antivirals, such as acyclovir or penciclovir cream, which work against the herpes virus on the skin.
Often considered when
A person has recognizable outbreaks and wants a topical option, usually started early, at the tingling stage.
Less suitable or needs caution when
Allergy to the ingredients. Creams are not for the eyes or inside the mouth. They are often less helpful than oral medicine for frequent or severe outbreaks.
What to watch for
Dryness, mild burning, or irritation at the spot.
How long to judge it
Benefit is usually small and is judged within a single outbreak.
Questions to ask
- Would a cream or a pill make more sense for me?
- How early do I need to act for it to help?
Procedures
What it is
Talking with your clinician before dental work, lip filler, laser, peels, or similar treatments, since skin injury can trigger an outbreak.
Often considered when
You have a history of cold sores and a procedure near the mouth is planned.
Less suitable or needs caution when
Not needed for procedures far from the mouth. Avoid elective procedures on the lips during an active outbreak.
What to watch for
An outbreak after a procedure, which can be mistaken for an infection or a reaction.
How long to judge it
Plan ahead of the procedure date.
Questions to ask
- Should I take any steps before a procedure near my mouth?
- Should this procedure wait if I have a sore?
Pills
What it is
Prescription antiviral pills in the acyclovir family (acyclovir, valacyclovir, famciclovir) that clinicians may discuss for treating an outbreak.
Often considered when
Outbreaks are painful, large, or frequent, or when starting treatment very early is important to the person.
Less suitable or needs caution when
Kidney problems, pregnancy or breastfeeding, and interactions with other medicines need to be reviewed by a clinician. Allergy to any of these drugs.
What to watch for
Headache, nausea, or stomach upset. Staying well hydrated matters. Tell your clinician if you have kidney disease.
How long to judge it
Usually judged within one outbreak. Benefit is greatest when started early.
Questions to ask
- Would an on-hand supply for outbreaks make sense for me?
- Are any of my other medicines a concern with this?
What it is
Taking an oral antiviral regularly over a period of time, under a clinician's direction, to lower how often outbreaks happen.
Often considered when
A person has frequent recurrences, outbreaks that are severe, or outbreaks tied to a predictable event, or has a weakened immune system or a history of complications.
Less suitable or needs caution when
Kidney disease, pregnancy or breastfeeding, or concern about taking a medicine long term. Needs periodic review.
What to watch for
Possible stomach upset or headache. Outbreaks may return after stopping.
How long to judge it
Clinicians often review benefit after several months.
Questions to ask
- Do my outbreaks happen often enough to consider this?
- How would we decide when to review or stop?
Lifestyle and holistic
What it is
Using a lip balm with broad-spectrum SPF, wearing a wide-brimmed hat, and limiting strong midday sun on the lips.
Often considered when
Sun seems to bring on your outbreaks, or you spend long hours outdoors, skiing, or at the beach.
Less suitable or needs caution when
Allergy to a balm ingredient. Do not share balm sticks, and skip any applied directly onto an active sore unless a clinician advises it.
What to watch for
Reapply after eating, drinking, or sweating. Balm in a tube that you squeeze out is more hygienic than a stick.
How long to judge it
Judged over a season or more, since outbreaks are irregular.
Questions to ask
- Do you think sun is a trigger for me?
- Which lip protection do you suggest for my skin tone?
The virus can wake up for reasons that are not always clear. Common triggers people report include:
- Sun and wind. Strong sunlight on the lips is a well-known trigger.
- Stress. Emotional or physical stress, and poor sleep, may play a role.
- Illness. Colds, flu, or fever (which is why they are called "fever blisters").
- Skin injury. Dental work, lip procedures, cosmetic treatments, or chapped, cracked lips.
- Hormone changes. Some people notice outbreaks around their period.
- Weaker immunity. From illness or from certain medicines.
Triggers vary a lot from person to person, and many outbreaks have no clear trigger. Keeping a simple note of what happened before each outbreak may help you spot your own pattern.
| Topic | Evidence | What it means |
|---|---|---|
| Stress and sleep | Early | Many people link outbreaks to stress or poor sleep, and some studies support a connection. The evidence is mixed and stress is hard to measure, so it may help to treat sleep and stress care as general health, not a guaranteed way to prevent outbreaks. |
| Sun and wind protection | Promising | Sunlight is a recognized trigger in studies, and lip SPF is a low-risk step. How much it reduces outbreaks in daily life is less certain. |
| Lysine and other supplements | Early | Some people take lysine or other supplements hoping to prevent cold sores. Research has been limited and mixed, so benefit is unproven. Talk with a clinician before starting supplements, especially with other medicines or health conditions. |
| Emotional impact and stigma | Established | Cold sores can cause embarrassment or worry about relationships, even though HSV-1 is very common. Honest, calm talks with partners and clinicians help. Mental health support is reasonable if the worry feels heavy. |
Read: Anti-inflammatory eating
Avoid very restrictive diets, especially for children, unless a clinician is guiding you.
Cold sores ·
When to get care soon
Contact a clinician promptly, or seek urgent care for the first two items, if you notice:
- Eye symptoms: eye pain, redness, light sensitivity, blurry vision, or blisters near the eye or on the eyelid. This needs prompt evaluation to protect vision.
- A newborn or young infant (under about 3 months) with a blister, sores, fever, or poor feeding, or a newborn exposed to someone with a cold sore. Herpes can be very serious in babies.
- Eczema or another skin condition with widespread painful blisters, punched-out sores, fever, or swollen glands. This could be eczema herpeticum, which is an emergency.
- A weakened immune system (for example from cancer treatment, an organ transplant, HIV, or immune-suppressing medicines) and a cold sore, especially one that is large, spreading, or slow to heal.
- A sore that lasts longer than 2 weeks, keeps getting bigger, or is unusually painful.
- Frequent recurrences that disrupt your life, or sores in places other than the lips.
- Signs of a bacterial infection: spreading redness, warmth, pus, or fever.
About the reviewer
Raashid Haque, MD
Board Certified Dermatologist · Charlotte, NC
- 25+ years of clinical experience
- Dermatology at University of Oklahoma - Chief Resident
- Internship at Baylor College of Medicine
- LSU School of Medicine Shreveport - Valedictorian, AOA