Canker sore

Aphthous Ulcers (Recurrent Aphthous Stomatitis, Aphthae, Canker Sores)

Recurrent aphthous stomatitis (RAS) is a common condition characterized by recurring ulcers confined to oral mucosa in patients with no other signs of disease. Patient presents with multiple round or ovoid ulcers generally with well-defined borders and erythematous halo surrounding the periphery of the ulcer.

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  Aphthous ulcer

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  Aphthous ulcer

Etiopathogenesis

Although many theories were proposed to explain the etiology of RAS, there appears to be no single causative factor. Various etiological factors have been proposed, such as hereditary, trauma, deficiency states, psychological factors, endocrine disorders, allergic conditions, infections, blood dyscrasias, drugs, GI diseases, urological disorders, dermatological disorders and immunologic origin, etc. Lehner (1964) and Dolly (1969) were of the opinion that RAS belonged to the group of autoimmune diseases. Lehner in 1969, found elevated levels of IgG and IgA in the sera of patients with RAS. A fluorescent antibody technique showed both IgG and IgM were binding by epithelial cells of the spinous layer of oral mucosa in RAS patients. Greenspan et al (1981) implicated antibody dependent cellular cytotoxicity as a pathogenic mechanism in RAS. Thomas and coworkers (1990) showed that T lymphocytes from RAS patients had increased cytotoxicity to oral epithelial cells.

Clinical features

• Individuals may experience burning sensation which may appear 2–48 hours before the ulcer appears. During the initial periods, a localized area of erythema develops within hours, a small white papule forms, ulcerates and gradually enlarges over the next 48–72 hours.
• The ulcers are usually regular and well defined. They are rimmed by an erythematous halo and the ulcer is covered with a yellowish-gray fibrinous pseudomembrane.
• The number and size of the ulcers vary based on the type of RAS.
• Ulcers are usually seen on the non-keratinized oral mucosa (commonly on the buccal and labial mucosa). Ulcers are rarely seen in the heavily keratinized palate or gingiva.

Types of recurrent aphthous stomatitis

Minor aphthous ulcers (Mikulicz ulcer)

The minor RAS are tiny round to ovoid ulcers that mainly involve the nonkeratinized oral mucosa (such as the buccal mucosa, labial mucosa, floor of mouth, ventral surface of the tongue). In most individuals one to six ulcers measuring about 2–4 mm in diameter are present at any given point of time. The ulcers are surrounded by an erythematous halo. These ulcers heal in about a week’s time without scarring.

Major aphthous ulcers (Sutton’s ulcers; periadenitis mucosa necrotica recurrents)

Like the name suggests these ulcers are larger in size (almost up to 1 cm in size) when compared to minor RAS. Major RAS involve even the keratinized areas of the oral mucosa (such as the palate and dorsum of tongue). These ulcers usually occur in very few numbers ranging from one to six at a time. They persist for a longer duration and heal in about 2–6 weeks with scarring.

Herpetiform ulcers

These are present as crops of tiny pin head sized ulcers which coalesce together. These may be present both on the keratinized as well as the nonkeratinized mucosa. These ulcers typically begin as tiny vesicles that subsequently ulcerate. These are extremely painful and tend to heal in about 10 days and almost immediately recur.

Diagnosis

The diagnosis of RAS is done by exclusion. Hematological examination can be performed to rule out blood dyscrasias. Ocular, genital, skin, or rectal lesions should not be present to make a diagnosis of aphthous stomatitis.

Photographic comparison of: 1) a canker sore – inside the mouth, 2) herpes, 3) angular cheilitis, and 4) chapped lips.

Management

The primary goals of therapy for RAS are relief of pain, reduction of ulcer duration, and restoration of normal oral function. Secondary goals include reduction in the frequency and severity of recurrences and maintenance of remission. Topical medications, such as antimicrobial mouthwashes and topical corticosteroids, can achieve the primary goals but have not been shown to alter recurrence or remission rates. Systemic medications can be tried if topical therapy is ineffective. Levamisole has shown variable effi cacy in reducing ulcer frequency and duration in patients with minor recurrent aphthous ulcer (RAU). Dose: 150 mg per day for 3 consecutive days followed by a gap of 2 weeks. Then repeat for 3 days. This is to be done 6 times (total therapy time is 3 months and total number of tablets is 18). Thalidomide is effective but, because of its toxicity and cost, should be used only as an alternative to oral corticosteroids.

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