Cold sores vs. canker sores: what are the differences?
Explore the key differences between canker and cold sores, how long it takes for recovery and when to see a doctor.
Cold sores and canker sores are two common, yet very different types of mouth sores that can make eating, talking and even smiling difficult. But how can you tell if you’re dealing with a cold sore or a canker sore? We’ll help you understand the differences.
From appearance to causes to treatment, let’s break down these annoying sores so you can understand what’s going on and feel better faster.
Want to feel like yourself in your smile again? Schedule an appointment with Aspen Dental for expert diagnosis and personalized treatment.
What is a cold sore?
A cold sore, a type of mouth sore, is a fluid-filled bump that eventually scabs over. It appears outside the mouth, typically on the lips, below the nose or even on the chin. It’s caused by the herpes simplex virus (usually HSV-1).
Here’s a typical lifecycle of a cold sore:
The warning stage: It starts with a tingle, itch or slight inflammation where the sore will appear. This is the time to act fast if you want to minimize the outbreak.
Blister stage: Small bumps develop and grow into painful blisters filled with fluid.
Scabbing stage: The blister bursts, releasing fluid and forms a crusty scab as it begins to heal.
Cold sores tend to stick around for 1-2 weeks and are extremely contagious. The virus can spread through direct contact (like kissing) or sharing items like utensils or lip balm.
Keeping hands clean and avoiding close contact while the sore is active are crucial to stop the spread.
What is a canker sore?
A canker sore, or aphthous ulcer, is a shallow, round sore that forms inside the mouth on soft tissue like cheeks, gums or under the tongue. It has a white, yellow or gray center with a red ring around it. Unlike a cold core, a canker sore is not caused by a virus and is not contagious.
Canker sores can happen for a variety of reasons, including poor oral hygiene, though sometimes the cause isn’t clear (even the experts at the National Institute of Dental and Craniofacial Research admit it).
Most canker sores heal on their own within 1–2 weeks, but larger ones (called major canker sores) may take up to 4 weeks and could leave scars. They can sting and be painful, but rest assured, they’re not contagious.
Key differences between cold sores and canker sores
Cold sores and canker sores may seem similar, but there are some major differences that set them apart. Here's a quick breakdown:
Appearance
Cold sores: Begin as small bumps and develop into fluid-filled blisters. Once they burst, they form scabs as they heal.
Canker sores: Are small, shallow ulcers with a white, yellow or gray surface and a red border.
Location
Cold sores: Typically found outside the mouth, on the lips, chin or near the nose.
Canker sores: Always inside the mouth, on soft tissue like your gums, cheeks or under the tongue.
Causes
Cold sores: Caused by the herpes simplex virus (HSV-1). They can be triggered by stress, illness, sun exposure or hormonal changes.
Canker sores: Have multiple causes, including minor injuries, poor oral hygiene, stress, certain foods, nutrient deficiencies, poor-fitting dentures or underlying conditions. Some cases occur for unknown reasons.
Contagiousness
Cold sores: Yes—highly contagious through direct contact or shared objects.
Canker sores: Not contagious at all.
Treatment
Cold sores: Over-the-counter and prescription antiviral medications can help shorten outbreaks. Cool compresses can also reduce discomfort.
Canker sores: Remedies like saltwater rinses, baking soda or honey can ease the pain. Severe cases might benefit from prescription antimicrobial mouthwash or topical steroids.
How long does it take to recover from cold sores and canker sores?
Cold sores and canker sores usually heal up in 1–2 weeks. Cold sores might clear up even faster if you catch them early and use antiviral meds. On the other hand, larger canker sores can take up to 4 weeks to fully heal.
For both types, keeping up with good oral hygiene and addressing issues early can help you avoid bigger problems or a longer recovery. If things don’t get better or start to feel worse, it’s definitely worth scheduling an appointment with Aspen Dental.
When to see a doctor
Most of the time, cold sores and canker sores will resolve on their own. However, you should see your doctor or dentist at Aspen Dental if:
The sore lasts longer than 2 weeks.
The sore is unusually large or worsening.
You experience a fever, swollen lymph nodes or severe pain.
Cold sores spread to other parts of your face or body.
You have frequent or recurring outbreaks.
You have a compromised immune system that may slow down recovery.
Cold sores vs. canker sores FAQs
What can help heal canker sores more quickly?
Canker sores often heal independently, but using a baking soda rinse or an antimicrobial mouthwash can speed up recovery. Eating gentle, non-irritating foods and staying hydrated can also help.
What are some similar conditions that resemble cold sores and canker sores?
Sometimes large pimples near the mouth and nose can look a lot like cold sores. Other conditions, like oral thrush or leukoplakia, can create textured patches in the mouth that might be mistaken for canker sores.
If you’re unsure or concerned about a mouth sore, reach out to your Aspen Dental care team.
How are canker sores and cold sores diagnosed?
If you think you might have a cold sore or canker sore, visiting your dentist or doctor is a great first step. They’ll do a full oral and facial exam, review your medical history and discuss any conditions that might be causing the sore or outbreak.
Can canker sores be caused by injury?
Yes, they can. Accidentally scraping the inside of your mouth with a toothbrush or toothpick, or biting your tongue or lip, can lead to a canker sore. Be gentle with dental tools and chew carefully to avoid those little injuries that can turn into sores.
Get treated for cold sores and canker sores
Mouth sores are uncomfortable and can take a toll on your daily life. Recognizing whether you’re dealing with a cold sore or a canker sore can make treatment quicker and more effective.
Still unsure about what’s causing your symptoms? Schedule an appointment with your local Aspen Dental. Our team is ready to help you understand the issue and find a solution tailored to your needs.