Mouth Ulcer Causes: The Reasons for Ulcerations In and Around the Mouth

We as dentists come across mouth ulcers in our practice on a regular basis. These mouth ulcers can range from simple self-healing ones to malignant carcinomas which can be fatal.

But what is the reason for these ulcerations that happen in and around the mouth?

Before looking at the various mouth ulcer causes, let’s try to know what a ‘mouth ulcer’ is, in the first place.

What is a Mouth Ulcer?

An ulcer is defined as a complete discontinuity of epithelium due to a pathological process. In simple terms, it is the breakage in the epithelial lining of our body due to some process which isn’t normal.

And when these ulcerations take place inside the mouth or on the lip area, they are commonly termed as ‘mouth ulcers’.

If there is a partial breakage in the epithelial lining due to pathological processes it is termed as ‘erosion’.

There are a few other terms that we need to understand before we look for mouth ulcer causes.

Vesicle: Vesicles are elevated blisters that contain clear fluid and are less than 1 cm in diameter.

Bullae: These are elevated blisters that contain clear fluid and are more than 1 cm in diameter.

Classification of Mouth Ulcer Causes

The main reasons for mouth ulcers can be classified into the following seven main categories.

  • Hereditary Causes
  • Viral Causes
  • Caused by Autoimmune Deficiency
  • Allergic Causes
  • Traumatic Causes
  • Neoplastic Causes
  • Miscellaneous Reasons

Hereditary Causes of Mouth Ulcers

In this category, a known disease that causes mouth ulcers is ‘Epidermolysis Bullosa’.

Epidermolysis Bullosa

This is actually a rare hereditary disease in which ‘bullae’ form on the skin and the mucous membranes following a mild to moderate trauma.

The milder form of this disease is called ‘Epidermolysis Bullosa Simplex’, which heals without forming any scars.

The more severe form of this disease is termed as ‘Epidermolysis Bullosa Dystrophica’, which produces scars while healing.

‘Epidermolysis Bullosa Dystrophica’, is the one which affects even the mouth and the pharynx.

Treating such patients for dental problems is an almost impossible task as a slight pressure on the lips and the oral tissues may cause ‘bullae’ to form which will then cause ulcerations.

Sadly the definitive cure for Epidermolysis Bullosa is still unknown.

Symptomatic relief may be given using local anesthetics and steroidal therapy. There have been cases in the past which have ended in death, which of course is very rare.

mouth ulcer causes

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Mouth Ulcers Caused by Viral Infections

Herpes Simplex Infections/Primary Herpetic Gingivostomatitis/Intraoral Recurrent Herpetic Stomatitis(IRHS)

Caused by Herpesvirus hominis this disease is a common cause of multiple ulcerations in the mouth.

This condition is characterized by Vesicles appearing on the vermillion border (sharp demarcation between the lip and the adjacent normal skin), acute onset of fever, headache, irritability and the pain and swelling in the associated lymph nodes.

What started as Vesicles later rupture and form pinpoint ulcers which make the lip appear bloody.
The good news is Primary Herpetic Gingivostomatitis is a self-limiting disease and usually heals within 8-14 days without any medical intervention.

However, to lessen the discomfort and accelerate the recovery process drugs may be used. The symptomatic relief can be given using mainly topical anesthetic gels, and mouthwashes.

Topical applications of Zovirax and Acyclovir may be helpful in immunocompromised patients.

Antipyretic medication can be given to control fever.

Drinking plenty of water and keeping the body hydrated is vital for fast recovery in case of viral infections.

Antiviral agents are the drugs of choice in severe cases as antibiotics are almost useless in viral infections. Also, the use of corticosteroids is contraindicated.

Herpes Zoster

This is a disease caused by the Varicella zoster virus, which is a DNA virus. This condition occurs in two forms. Primary infection and recurrent infection.

The primary infection caused by Varicella zoster is termed ‘chicken pox’, which occurs in an individual who contacts the infection the very first time.

Once the ‘chicken pox’ is healed the Varicella zoster virus becomes latent and remains in the dorsal root ganglia of spinal nerves or extramedullary ganglia of cranial nerves.

This virus may get reactivated later in life in some individuals. This reactivated infection causes lesions of localized Herpes Zoster.

Remember, chicken pox is a childhood disease whereas Herpes zoster appears in adults.

Herpes zoster is a severe form of the diseases and may cause secondary complications in some cases, more so if the infection becomes generalized and involves internal organs.

Postherpetic neuralgia is a result of such complication which is caused by the inflammation and fibrosis of the affected nerve. This condition may cause severe pain for months and sometimes years after the lesions have healed.

This condition is characterized by ulcerations in the mouth area and the trigeminal nerve is the most commonly involved.


This is a disease caused by Coxsackie A4 virus in most cases, and by coxsackie A1 to A10 and A15 to A22 in some cases.

This condition is characterized by the formation of small vesicles bilaterally inside the mouth in the area of pharynx, tonsils, faucial pillars and soft palate. This is associated with symptoms of fever, chills, and anorexia.

The person will also have a sore throat, sore mouth along with difficulty in swallowing. The vesicles that are formed usually rupture in 24-48 hours and form ulcerations inside the mouth.

The disease isn’t severe and usually heals within 7 to 10 days.

So the treatment is mainly concentrated on keeping the individual hydrated and controlling fever. Also, topical anesthetics can be used to relieve irritability and pain, especially when swallowing.

Hand Foot and Mouth Disease

This disease caused by Coxsackie A 16 virus.

Hand foot and mouth disease is characterized by the formation of oral vesicles along with pruritic(itchy) macule (an area of skin discoloration) and papule (a small pimple or swelling on the skin, often forming part of a rash).

Vesicles appear in the mouth and macule and papule mostly appear on the extensor surfaces of the hands and feet.

Lesions in the mouth in this disease are more extensive in nature and can be found on almost all the surfaces in the mouth.

The treatment options for ‘Hand foot and mouth disease’ are similar to that in Herpangina.

Hoof and Mouth Disease

This is a disease more commonly seen in cattle and other cloven-hoofed animals and is occasionally transmitted to humans.

This disease is characterized by the formation of vesicles inside the mouth and on the palm of the hand, soles of the feet and also in-between the fingers.

The vesicles gradually increase in size and then rupture forming a scar while healing. Treatments are mostly symptomatic and the infection gradually heals after 10-15 days, in most cases.

Mouth Ulcers Caused By Autoimmune Diseases

Erythema Multiforme

This is an acute disease of the skin and mucous membrane that may cause a variety of skin lesions, hence the name ‘multiforme’.

The oral lesions appear mostly in the form of bullae and are often accompanied with similar skin lesions.

The lesions that are formed rupture rapidly sometimes forming irregular bleeding ulcers. The individual who is suffering from ‘Erythema Multiorme’ finds it very difficult to it.

The disease heals itself within a matter of 2-3 weeks in case of mild to moderate infections. In severe cases, it may take several weeks.

The severe form of ‘Erythema Multiforme’ is called ‘Stevens-Johnson Syndrome’.

Acute Epidermal Necrolysis

This disease is characterized by large bullae (on the skin and inside the mouth) and peeling of the skin, often with the mucous membrane involvement.

Aphthous Ulcers

Aphthous ulcers are the most common type of oral ulcers. These are also called Canker sores or Recurrent aphthous stomatitis or RAS.

We have given in detail about Canker sores here.

When Recurrent aphthous stomatitis appears along with Recurrent genital ulcers and Eye lesions, the condition is called ‘Bechet’s disease’.

Pemphigus Vulgaris

Pemphigus vulgaris is a potentially fatal autoimmune disease that affects the skin and the mucosa.

This disease is characterized by the formation of thin-walled bullae, which form on the skin, in the mouth and other mucosal layers of the body.

The bulla usually breaks rapidly forming large ulcerations. But this continues to extend peripherally which leave large denuded areas.

This is a disease which may cause even death in some people if it becomes severe.

Treatment involves the use of systemic corticosteroids. 100mg/day of Prednisolone is the drug of choice initially which may be tapered later depending on the condition.

Bullous Pemphigoid

Occurs chiefly in children under 5 years of age and adults over 60. The lesions in this condition are less severe and extensive than the ones seen in pemphigus vulgaris.

The ulcerations in the mouth are caused by vesicles which form and rupture slowly and are often less painful.

This condition is managed with systemic corticosteroids.

Cicatricial Pemphigoid

This is a chronic disease which mainly appears in people aged above 50 years. The lesions in the mouth are a common occurrence more so on the gums (gingiva).

Mouth Ulcers Caused by Trauma

Also called as traumatic ulcers, these may have been caused by mechanical, chemical, thermal, accidental, or self-inflicted injuries.

These may also be formed as a side effect of certain treatments.

One of the most common causes of traumatic ulcers in the mouth is faulty dentures and toothbrush trauma. If the ulcer is caused by denture, replace the denture or repair it ASAP. You need to keep the denture out for several days till the ulcer heals. This is a case where you need to visit your dentist immediately.

If the ulcer is caused by toothbrush trauma, you need to refine your toothbrushing technique. Also changing the toothbrush to soft bristled one will greatly help. Visit the dental office for more information regarding this.

Miscellaneous Mouth Ulcer Causes

Erosive Lichen Planus

This is a premalignant condition which is characterized by ulcerations in the mouth. The treatment options depend on the biopsy report.

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Medical Disclaimer

This content is strictly the opinion of the author and is for informational and educational purposes only. It is not intended to provide medical/dental advice or to take the place of medical advice or treatment from a personal physician or a dentist. All readers/viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions.

The publisher of this content takes NO responsibility for possible health consequences of any person or persons reading or following the information in this educational content. All viewers of this content, especially those taking prescription or over-the-counter medications, should consult their physicians and/or the dentists before beginning any nutrition, supplement, medications or lifestyle program.

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