Approach Considerations
It is important to rule out any underlying cause in the case of oral ulcers. A thorough history is essential, since this and a review of systems can assist the clinician in determining whether ulcers are related to a systemic inflammatory process or are truly idiopathic. Diseases causing oral ulcers that should not be mistaken for recurrent aphthous stomatitis (RAS) include Behçet syndrome, cyclic neutropenia, recurring intraoral herpes infections, human immunodeficiency virus (HIV)–related oral ulcers, and gastrointestinal diseases such as Crohn disease and ulcerative colitis. Minor aphthous ulcers (MiAUs) most commonly form on nonkeratinized oral mucosa, usually on the buccal and labial mucosa; they have a duration of about 10-14 days without scar formation. [2]
Laboratory Studies
See the list below:
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Systemic disorders should particularly be suspected in the presence of features that may suggest a systemic background.
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Diagnosis of recurrent aphthous stomatitis (RAS) is based on history and clinical features. No specific tests are available; however, to exclude systemic disorders discussed above, the following tests may be helpful:
Complete blood cell count
Hemoglobin test
White blood cell count with differential
Red blood cell indices
Iron studies (usually an assay of serum ferritin levels)
Red blood cell folate assay
Serum vitamin B-12 measurements
Serum antiendomysium antibody and transglutaminase assay (positive in celiac disease)
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Rarely, biopsy may be indicated in cases in which a different diagnosis is suspected. Occasionally, for example, pemphigus may mimic RAS. Occasional RAS can mimic a neoplasm, necrotizing sialometaplasia, or TUGSE (traumatic ulcerative granuloma with stromal eosinophilia).
Histologic Findings
The histology of RAS is nonspecific. The ulcer is depressed well below the surface, and the inflammation extends deeply. The surface of the ulcer is covered by a fibrinous exudate infiltrated by polymorphs. Beneath is a layer of granulation tissue with dilated capillaries and edema. Deeper still is a repair reaction, with fibroblasts in the surrounding connective tissue laying down fibrous tissue.
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Traumatic ulcer on ventrum/lateral margin of tongue; these must be differentiated from aphthae.
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Recurrent aphthae in floor of mouth, showing ovoid ulcer with inflammatory halo.
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Typical aphthous ulcer in a common site, showing inflammatory halo surrounding a yellowish round ulcer.
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Recurrent aphthous ulcer with well-defined erythematous halo and central yellowish gray base, on left anterolateral tongue.
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Recurrent aphthous stomatitis with ulcers of varying sizes - large ulcers on the right buccal mucosa and a small ulcer on the anterior tongue.