Overview
It starts as a slight tingle a small, irritating bump on your inner cheek or tongue. Within a day, it’s a full-blown crater of pain. Eating your favorite meal can feel like a battle, and even casual conversation may seem taxing. Mouth ulcers are a universal affliction; while prevalence in specific regions like Africa is hard to pinpoint, millions experience these painful sores worldwide. So, what exactly are they, and what can you do about them? Let’s take a closer look.
What is a mouth ulcer ?
A mouth ulcer is a small, painful sore that occurs on the soft tissues inside the mouth—such as the gums, lips, inner cheeks, or tongue. They typically present with a white or yellowish center surrounded by a red, inflamed border. Importantly, they’re distinct from cold sores, which are viral and highly contagious; most mouth ulcers are harmless, though persistent ones may signal deeper issues.
Types of mouth ulcer
The most common type is a canker sore (aphthous ulcer), categorized as minor (small and heal quickly), major (larger and more painful), or herpetiform (clustered sores). Other ulcers may result from injury, infection, or systemic health conditions. Appearance, duration, and accompanying symptoms help differentiate them.
Symptoms and Causes
What are the symptoms of a mouth ulcer ?
These ulcers cause sharp, localized pain, especially when eating or drinking. Visually, they appear as round or oval sores with a white, yellow, or gray center and a bright red border. You may experience one ulcer or multiple simultaneously.
What causes mouth ulcer ?
Triggers vary from accidental cheek bites, stress, hormonal shifts, lack of sleep, to irritation from abrasive dental products. Nutritional deficiencies also play a role. These factors compromise the protective lining of the mouth, making it prone to ulceration.
Health conditions associated with mouth ulcer
While many ulcers are benign, recurring or long-lasting ones may signal underlying issues such as iron or vitamin B12 deficiencies, viral infections (e.g., herpes simplex), autoimmune disorders, or gastrointestinal conditions like Crohn’s disease.
Are mouth ulcers contagious ?
No—they are not contagious. Unlike cold sores, they cannot be passed on through kissing, sharing utensils, or other contact.
Diagnosis and Tests
How do health providers diagnose mouth ulcer ?
Diagnosis is usually based on visual inspection. However, if ulcers are severe, persistent, or recurrent, a clinician may order blood tests (e.g., to check for deficiency) or, in rare cases, a biopsy to rule out malignancy.
Management and Treatment
How do you treat a mouth ulcer ?
Fortunately, most ulcers heal within 1–2 weeks. Pain relief may include OTC antiseptic gels, steroid mouth rinses, or protective coatings. For more stubborn cases, stronger topical prescriptions may be necessary.
How to cure mouth ulcer fast naturally
Saltwater rinses or diluted hydrogen peroxide help soothe and clean the area. Avoid hot, spicy, or acidic foods that exacerbate discomfort and stay well-hydrated.
Outlook / Prognosis
How long do mouth ulcer last ?
Typical ulcers resolve in 1–2 weeks. Major aphthous ulcers may take up to 6 weeks and might leave scars. Healing time often shortens when primary causes like nutritional deficits are addressed.
Prevention
Can I prevent mouth ulcer ?
Prevention focuses on identifying and avoiding triggers. Gentle oral hygiene, including soft-bristled brushing and regular flossing, is essential. A well-balanced diet supports oral health and reduces risk.
Living With
When should I see my healthcare provider ?
Seek help if an ulcer lasts more than 3 weeks, new sores appear before old ones heal, OTC treatments fail, or if you experience systemic symptoms like fever or diarrhea.
What questions should I ask my healthcare provider ?
Consider asking:
-
Should I modify my diet or oral care routine?
-
Are there treatments to speed healing or reduce pain?
-
Should I be evaluated for underlying conditions?
Additional Common Questions
Mouth ulcer vs. canker sore: What’s the difference ?
A canker sore is a specific type of mouth ulcer. While all canker sores are mouth ulcer, not all mouth ulcer are canker sores.
How do you know if your mouth ulcer is bad ?
It may be considered "bad" if it is unusually large, extremely painful, persistent (lasting more than three weeks), or if it's accompanied by other symptoms like fever, skin rashes, or difficulty swallowing. These can be signs of a more serious underlying condition.
Are mouth ulcer a sign of cancer ?
It's a scary thought, but one that doesn't heal is a potential sign of oral cancer. While the vast majority of ulcers are benign, if you have a sore that persists for more than three weeks, especially on or under your tongue, you should see a healthcare provider to get it checked out. It's always better to be safe than sorry!
Are mouth ulcer contagious?
No, they are not contagious. Unlike cold sores, which are caused by the herpes simplex virus and can be transmitted through close contact, mouth ulcer are not infectious and cannot be spread by kissing or sharing food and drinks.
Published 12th August 2025
References
Cleveland Clinic, Mouth Ulcer, Available at: https://my.clevelandclinic.org/health/diseases/21766-mouth-ulcer
NHS, Mouth ulcer, Available at: https://www.nhs.uk/conditions/mouth-ulcers/
MSD Manuals, Mouth Sores and Inflammation, Available at: https://www.msdmanuals.com/home/mouth-and-dental-disorders/symptoms-of-oral-and-dental-disorders/mouth-sores-and-inflammation