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Recurrent Aphthous Stomatitis


Bernard J. Hennessy

, DDS, Texas A&M University, College of Dentistry

Reviewed/Revised Jan 2024
Topic Resources

Recurrent aphthous stomatitis (RAS) is a common condition in which round or ovoid painful ulcers recur on the oral mucosa. Etiology is unclear. Diagnosis is clinical. Treatment is symptomatic and most often includes topical corticosteroids.


  • 1. Akintoye SO, Greenberg MS: Recurrent aphthous stomatitis. Dent Clin North Am 58(2):281-297, 2014. doi: 10.1016/j.cden.2013.12.002

Etiology of Recurrent Aphthous Stomatitis

Etiology is unclear, but RAS tends to run in families. The damage is predominately T-cell–mediated. Cytokines, such as IL-2, IL-10, and particularly TN-alpha, play a role.

Predisposing factors include

  • Oral trauma

  • Stress

Some patients with food allergies may also have RAS and certain foods may exacerbate symptoms (eg, chocolate, peanuts, eggs). However, there are no studies directly linking food allergy as the cause of RAS.

Symptoms and Signs of Recurrent Aphthous Stomatitis

Symptoms and signs usually begin in childhood (most patients are < 30 years) and decrease in frequency and severity with aging. Symptoms may involve as few as one ulcer 2 to 4 times a year or almost continuous disease, with new ulcers forming as old ones heal. A prodrome of pain or burning for 1 to 2 days precedes ulcers, but there are no antecedent vesicles or bullae. Severe pain, disproportionate to the size of the lesion, can last from 4 to 7 days.

Aphthous ulcers are well-demarcated, shallow, ovoid, or round and have a necrotic center with a yellow-gray pseudomembrane, a red halo, and slightly raised red margins.

Minor aphthous ulcers (canker sores) account for 85% of cases (1 Symptoms and signs reference Recurrent aphthous stomatitis (RAS) is a common condition in which round or ovoid painful ulcers recur on the oral mucosa. Etiology is unclear. Diagnosis is clinical. Treatment is symptomatic... read more Symptoms and signs reference ). They occur on the floor of the mouth, lateral and ventral tongue, buccal mucosa, and pharynx; are < 8 mm (typically 2 to 3 mm); and heal in 10 days without scarring.

Major aphthous ulcers (Sutton disease, periadenitis mucosa necrotica recurrens) constitute 10% of cases. Appearing after puberty, the prodrome is more intense and the ulcers are deeper, larger (> 1 cm), and longer lasting (weeks to months) than minor aphthae. They appear on the lips, soft palate, and throat. Fever, dysphagia, malaise, and scarring may occur.

Herpetiform aphthous ulcers (morphologically resembling but unrelated to herpesvirus) account for 5% of cases. They begin as multiple (up to 100) 1- to 3-mm crops of small, painful clusters of ulcers on an erythematous base. They coalesce to form larger ulcers that last 2 weeks. They tend to occur in women and at a later age of onset than do other forms of recurrent aphthous stomatitis.

Symptoms and signs reference

  • 1. Akintoye SO, Greenberg MS: Recurrent aphthous stomatitis. Dent Clin North Am 58(2):281-297, 2014. doi: 10.1016/j.cden.2013.12.002

Diagnosis of Recurrent Aphthous Stomatitis

  • Clinical evaluation

Evaluation proceeds as described previously under stomatitis Stomatitis Oral inflammation and ulcers, known as stomatitis, may be mild and localized or severe and widespread. They are invariably painful. (See also Evaluation of the Dental Patient and Gingivitis... read more Stomatitis . Diagnosis is based on appearance and on exclusion because there are no definitive histologic features or laboratory tests.

Primary oral herpes simplex Herpes Simplex Virus (HSV) Infections Herpes simplex viruses (human herpesviruses types 1 and 2) commonly cause recurrent infection affecting the skin, mouth, lips, eyes, and genitals. Common severe infections include encephalitis... read more Herpes Simplex Virus (HSV) Infections may mimic RAS but usually occurs in younger children, always involves the gingiva, may affect any keratinized mucosa (hard palate, attached gingiva, dorsum of tongue), and is associated with systemic symptoms. Viral culture can be done to identify herpes simplex. Recurrent herpetic lesions are usually unilateral.

Similar recurrent episodes, often with multiple ulcers, can occur with Behçet disease Behçet Disease Behçet disease is a multisystem, relapsing, chronic vasculitic disorder with mucosal inflammation. Common manifestations include recurrent oral ulcers, ocular inflammation, genital ulcers, and... read more Behçet Disease , inflammatory bowel disease Overview of Inflammatory Bowel Disease Inflammatory bowel disease (IBD), which includes Crohn disease and ulcerative colitis, is a relapsing and remitting condition characterized by chronic inflammation at various sites in the gastrointestinal... read more , celiac disease Celiac Disease Celiac disease is an immunologically mediated disease in genetically susceptible people caused by intolerance to gluten, resulting in mucosal inflammation and villous atrophy, which causes malabsorption... read more Celiac Disease , HIV infection Human Immunodeficiency Virus (HIV) Infection Human immunodeficiency virus (HIV) infection results from 1 of 2 similar retroviruses (HIV-1 and HIV-2) that destroy CD4+ lymphocytes and impair cell-mediated immunity, increasing risk of certain... read more Human Immunodeficiency Virus (HIV) Infection , PFAPA (periodic fevers with aphthous stomatitis, pharyngitis, and adenitis) syndrome PFAPA Syndrome PFAPA (periodic fevers with aphthous stomatitis, pharyngitis, and adenitis) syndrome is a periodic fever syndrome that typically manifests between ages 2 years and 5 years; it is characterized... read more , and nutritional deficiencies; these conditions generally have systemic symptoms and signs. Isolated recurrent oral ulcers can occur with herpes infection, HIV, and, rarely, nutritional deficiency (eg, zinc, iron, various B vitamins). Viral testing and serum tests can identify these conditions.

Drug reactions may mimic RAS but are usually temporally related to ingestion. However, reactions to foods or dental products may be difficult to identify; sequential elimination may be necessary.

Treatment of Recurrent Aphthous Stomatitis

  • Topical chlorhexidine and corticosteroids

Chlorhexidine gluconate mouthwashes and topical corticosteroids, the mainstays of therapy, should be used during the prodrome, if possible. The corticosteroid can be dexamethasone 0.5 mg/5 mL 3 times a day used as a rinse and then expectorated or clobetasol ointment 0.05% or fluocinonide ointment 0.05% in carboxymethylcellulose mucosal protective paste (1:1) applied 3 times a day. Patients using these corticosteroids should be monitored for candidiasis Candidiasis (Mucocutaneous) Candidiasis is skin and mucous membrane infection with Candida species, most commonly Candida albicans. Infections can occur anywhere and are most common in skinfolds, digital... read more Candidiasis (Mucocutaneous) . If topical corticosteroids are ineffective, prednisone (eg, 40 mg orally once a day) may be needed for 5 days.

Symptomatic treatment with topical anesthetics (eg, benzocaine with instructions to avoid toxicity) and/or surface protectants (eg, sucralfate) are effective in relieving discomfort, but these medications simply provide pain relief and/or a protective coating for tissue and are not therapeutic.

Continuous or particularly severe RAS is best treated by a specialist in oral medicine. Treatment may require prolonged use of systemic corticosteroids, azathioprine or other immunosuppressants, pentoxifylline, or thalidomide. Intralesional injections can be done with betamethasone, dexamethasone, or triamcinolone. Supplemental B1, B2, B6, B12, folate, or iron lessens RAS in some patients.

Drugs Mentioned In This Article

Drug Name Select Trade
Betasept, Chlorostat, DYNA-HEX, Hibiclens, Oro Clense , Peridex, Periogard, PerioRx , Perisol
AK-Dex, Baycadron, Dalalone, Dalalone D.P, Dalalone L.A, Decadron, Decadron-LA, Dexabliss, Dexacort PH Turbinaire, Dexacort Respihaler, DexPak Jr TaperPak, DexPak TaperPak, Dextenza, DEXYCU, DoubleDex, Dxevo, Hemady, HiDex, Maxidex, Ocu-Dex , Ozurdex, ReadySharp Dexamethasone, Simplist Dexamethasone, Solurex, TaperDex, ZCORT, Zema-Pak, ZoDex, ZonaCort 11 Day, ZonaCort 7 Day
Clobetavix, Clobevate, Clobex, Clodan, Cormax, Embeline, Embeline E, Impeklo, Impoyz, Olux, Olux-E, Olux-Olux-E Complete Pack, Temovate, Temovate E, Temovate Scalp, Tovet
Fluovix, Fluovix Plus, Lidex, Lidex -E, Vanos
Deltasone, Predone, RAYOS, Sterapred, Sterapred DS
Advocate Pain Relief Stick, Americaine, Anbesol, Anbesol Baby , Anbesol Jr , Banadyne-3, Benzodent, Benz-O-Sthetic, Boil-Ease, Cepacol Sensations, Chloraseptic, Comfort Caine , Dry Socket Remedy, Freez Eez, HURRICAINE, HURRICAINE ONE, Little Remedies for Teethers, Monistat Care, Orabase, OraCoat CankerMelts, Orajel, Orajel Baby, Orajel Denture Plus, Orajel Maximum Strength, Orajel P.M., Orajel Protective, Orajel Severe Pain, Orajel Swabs, Orajel Ultra, Oral Pain Relief , Oticaine , Otocain, Outgro, Pinnacaine, Pro-Caine, RE Benzotic, Topex, Topicale Xtra, Zilactin-B
Azasan, Imuran
Pentopak, Pentoxil , Trental
Adbeon, Alphatrex, Beta 1 Kit, Beta Derm , Betanate , Betatrex, Beta-Val, BSP 0820, Celestone, Del-Beta , Diprolene, Diprolene AF, Diprosone, Luxiq Foam, Maxivate, ReadySharp Betamethasone, Sernivo, Valisone
Aristocort, Aristocort A, Aristocort Forte, Aristocort HP, Aristo-Pak, Aristospan, Azmacort, Children's Nasacort Allergy 24HR Nasal Spray, Cinalog, Cinolar, Flutex, Hexatrione, Kenalog, Kenalog in Orabase, Kenalog-10, Kenalog-40, Kenalog-80, Nasacort, Nasacort AQ, Oralone, SP Rx 228 , Tac-3 , Triacet , Triamonide , Trianex , Triderm , Triesence, XIPERE, Zilretta
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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