Cold Sores Vs Canker Sores

Cold Sores Vs Canker Sores

Many people are not aware that “cold sores” and “canker sores” are two different entities and use these terms interchangeably. It is important to understand the differences between these two lesions, to seek proper diagnosis and treatment and to practice preventative measures.

If you have a history of recurrent ulcers on your lips, or near your lips, and they tend to recur on a particular side, then you are dealing with recurrent herpetic ulcers. These “cold sores” or “fever blisters” are viral in origin. The virus that causes them is the Herpes Simplex Virus (HSV). This type of ulcer is rarely found in the mouth, but when it occurs, the lesions will be found on the tissues that cover bone, i.e. the palate and gums. They also tend to recur in the same area.

If you have a history of recurrent ulcerations inside your mouth, located on the mobile tissues of the inner cheek, lips and floor of the mouth, you most likely suffer from apthous ulcers or “canker sores”. Apthous ulcers are not caused by a virus. Their etiology is believed to be an immune system response.

Treatments for herpetic lesions and apthous ulcers differ, but prevention is critical to both.

There is no cure for recurrent herpes. The virus resides in the trigeminal nerve ganglia of the infected individual.  Most individuals become infected during infancy or childhood, via infected family members or friends, through contact such as kissing, sharing eating utensils or sharing towels. It is important to note the disease can be transmitted even in the absence of visible lesions. 

When the virus is reactivated by local or systemic stimuli, such as trauma or exposure to UV light, the virus is replicated and travels through the nerve and forms it’s characteristic lesions. By the time you are aware a lesion is forming, it is too late. That is why the primary treatment is prevention. You need to be aware of and document what triggers your outbreaks, then you can make whatever changes are realistic to reduce these occurrences. The single most common trigger is UV radiation. You can minimize attacks by the simple act of using lip balm with a sun block of at least 30 every day. It is also wise to wear a wide brimmed hat or cap when possible.

When you have a HSV recurrence, a tingling, burning or itching sensation may occur before any lesions erupt. This is the ideal time to begin application of topical medications that may diminish symptoms. Penciclovar (Denavir) cream or Docosanol (Abreva) cream may be prescribed by your dentist. It is imperative that you apply them at the first indication of a recurrence in order to be effective.

Prevention is also critical to avoid apthous ulcers. You need to become aware of what triggers your outbreaks and make appropriate lifestyle changes. For some people this will mean eliminating certain foods. Researchers suggest eliminating each of the following foods one at a time to see if your occurrences of ulcers decreases. Documented trigger foods for apthous ulcers may include, but are not limited to, chocolate, nuts, shellfish, French mustard, citrus fruit, pineapples, figs, whole wheat, rye and barley. Keeping a food diary will help document your own individual food/ulcer relationships.

Trauma is another major cause of apthous ulcers. Certain foods are more likely to scrape the mouth. These include hard candy, snack chips or pretzels. Brushing too hard or using toothpicks, interproximal brushes or flossing too aggressively can lead to oral trauma and a recurrence of ulcers.

Dental research shows that an ingredient found in most toothpaste appears to be a significant trigger in recurrence of canker sores. The ingredient, sodium lauryl sulfate (SLS), is what creates the foaming action we associate with toothpaste. Ask your dentist to recommend a SLS-free toothpaste and you may experience a significant reduction in your outbreaks.

Triclosan, an antimicrobial agent added to some mouth rinses, has been shown to have some anti-inflammatory and analgesic effects to help ease the symptoms of canker sores.

For more severe cases of apthous ulcers, known as clusterform apthae and recurrent scarring apthae, treatment will vary on an individual basis and may range from tetracycline or steroid mouth rinses to systemic steroids and antibiotic therapy.

By understanding the difference between cold sores and canker sores, consulting with your dentist for proper diagnosis and treatment and practicing preventive measures, you may avoid a lot of needless suffering.

Dr. Stephen Petras

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