What Causes Canker Sores in the Mouth? Common Triggers and How to Prevent Them

You have a painful sore in your mouth, and you are wondering what it is and what caused it. It could be a canker sore. 

These small ulcers are not contagious, but they can be uncomfortable. Understanding the causes can help you prevent them from coming back and improve your oral health.

This blog will explain why canker sores form, what triggers them, and how to manage them for a faster recovery. 

If you have concerns about your oral health, read I Have White Patches in My Mouth, Should I Be Worried? to learn more about potential dental conditions.

What Are Canker Sores?

Canker sores, or aphthous ulcers, are small, shallow ulcers that develop inside the mouth.

They often appear on the inner lips, cheeks, tongue, or soft palate. They typically present as a white spot, with a red halo. Unlike cold sores, canker sores are not caused by a virus and are not contagious. Most heal on their own within 7 to 14 days without leaving scars.  

What Causes Canker Sores in the Mouth

There is no single cause for them, but several factors can contribute to their development:

• Minor oral injuries: Accidentally biting your cheek, aggressive brushing with a hard toothbrush, or irritation from braces or dental appliances.
• Stress and hormonal changes: Emotional stress, fatigue, or hormonal fluctuations can trigger outbreaks of canker sores.
• Acidic or spicy foods: Citrus fruits, tomatoes, chocolate, coffee, carbonated drinks, and salty foods can irritate delicate mouth tissues.
• Nutritional deficiencies: Lack of iron, vitamin B12, or folic acid can contribute to frequent sores.
• Food allergies or sensitivities: Some people react to certain ingredients like gluten, dairy, or acidic fruit.
• Underlying health conditions: Sores may be linked to autoimmune disorders, inflammatory bowel disease, or immune system deficiencies.

Can Canker Sores Be Mistaken for Something Else?

Yes, sores can resemble other types of mouth ulcers that cause similar symptoms. Here are some common look-alikes:

• Cold sores (Fever blisters): Caused by the herpes simplex virus type 1, cold sores appear as fluid-filled blisters outside the mouth, usually around the lips. Unlike canker sores, they are highly contagious.
• Oral thrush: A fungal infection causing white sores or patches in the mouth that can be wiped off. They are common in people with weakened immune systems or those taking antibiotics.
• Leukoplakia: Thick, white patches that do not scrape off, often linked to smoking, ill-fitting dental appliances, or chronic irritation. It should be checked by a dentist or oral health professional.
• Oral lichen planus: A chronic inflammatory condition causing white, lace-like patches or painful sores inside the mouth. It does not heal quickly like a simple canker sore.
• Hand, foot, and mouth disease (HFMD): A viral infection in children caused by Coxsakie viruses that causes painful mouth sores, fever, and a rash on the hands and feet.
• Behçet’s disease: A rare autoimmune disorder that causes recurrent canker sores, along with eye inflammation and genital sores.
• Oral cancer: A persistent sore that does not heal within two weeks, bleeds easily, or causes numbness may require evaluation by a dentist or cancer specialist. The most common types of oral cancer are squamous cell carcinoma, melanoma, and basal cell carcinoma. 

If you are unsure whether you have a canker sore or another condition, see a dentist for a physical exam if:

• The sore lasts longer than two weeks.
• It is unusually large or extremely painful.
• You have major canker sores that interfere with eating.
• The sore is accompanied by fever, swollen lymph nodes, or difficulty eating.

How to Treat and Prevent Canker Sores

Most canker sores heal on their own, but you can take steps to relieve discomfort and speed up the healing process.

Treatment options:

• Use a saltwater or baking soda rinse to reduce irritation.
• Apply over-the-counter oral gels with benzocaine or hydrogen peroxide for pain relief.
• Avoid spicy foods, acidic foods, and rough-textured foods that can worsen irritation.
• Use a soft-bristled toothbrush to prevent soft tissue damage.
• Take vitamin supplements if vitamin deficiencies may be a factor.
• Stay hydrated to keep your oral tissues healthy and promote healing.
• Try OTC mouthwash designed for mouth ulcers or a special mouthwash recommended by your dentist.
• Consider oral medications or topical medicine for persistent or complex canker sores.

Prevention tips:

• Manage stress with relaxation techniques like deep breathing or meditation.
• Maintain good oral hygiene by brushing and flossing gently to prevent irritation.
• Avoid known food triggers like citrus, coffee, spicy foods, and sour foods.
• Ensure a balanced diet rich in iron, vitamin B12, and folic acid to support immune function.
• Check for underlying medical conditions if sores are frequent or severe.
• Avoid abrasive foods or crunchy food that may damage delicate mouth tissues.
• Drink warm water instead of extremely hot foods or drinks that may trigger sensitivity.
• Get a physical exam or blood tests if you suspect an underlying medical condition is causing your symptoms.

Power Road Dental Care: Your Partners in Oral Health

If you experience frequent or painful sores, Power Road Dental Care can help.

Our team provides expert guidance to identify triggers, recommend treatments, and ensure your dental health stays on track.If you are in the Phoenix East Valley, book an appointment at our dental office in Mesa, AZ, call (480) 664-1438 or visit us at 2500 South Power Road, Suite 102, Mesa, AZ.