6-21: Aphthous Ulcers (Canker Sores)

Clinical Summary

Aphthous ulcers are shallow, 1- to 15-mm, painful mucosal ulcers. A prodromal burning sensation may be noted 2 to 48 hours before an ulcer is noted. The initial lesion is a small white papule that ulcerates and enlarges over 48 to 72 hours. Lesions are typically round or ovoid with a raised yellow border and surrounding erythema. Multiple aphthous ulcers may occur on the lips, tongue, buccal mucosa, floor of the mouth, or soft palate. Spontaneous healing occurs in 7 to 10 days without scarring. The exact etiology is unknown but is believed to involve an immune response to various triggers. Deficiencies of vitamin B₁₂, folic acid, and iron as well as viruses have been implicated. Stress, local trauma, and immunocompromised states have all been cited as possible precipitators.

Primary or recurrent herpetic oral lesions may present with an almost identical prodrome and similar appearance. Herpetic lesions, unlike aphthous ones, tend to occur on the gingiva, hard palate, and vermilion border. Oral erythema multiforme may also present similarly to aphthous stomatitis; however, like oral herpes, it may tend to present with multiple vesicles in the early stages. Stevens-Johnson syndrome represents a severe form of erythema multiforme characterized by hemorrhagic anogenital and conjunctival lesions as well as oral lesions. Herpangina results from coxsackieviruses and Echoviruses, with oral ulcerations typically involving the posterior pharynx. Oral pemphigus should also be considered. Behçet disease can present with recurrent oral lesions, genital ulcers, and uveitis.

Management and Disposition

Supportive care, rehydration, and pain control constitute the focus of therapy. A topical anesthetic agent such as 2% viscous lidocaine or liquid antihistamine/antacid mix as an oral rinse every 3 to 4 hours is palliative. Use of oral antimicrobial rinses promotes healing. Protective dental paste may be applied every 6 hours to prevent irritation of lesions. Triamcinolone acetonide in an emollient dental paste three to four times daily may reduce pain and promote healing.

Pearls

1. Aphthous ulcers may be associated with Crohn disease.

2. Topical anesthetics may be used as a temporary adjunct in pain relief. Care must be taken to avoid overdose or complications such as methemoglobinemia from overuse.

3. Aphthous ulcers almost never occur on gums or hard palate.