Recurrent Aphthous Stomatitis and Herpes Labialis: A Comparative Clinical Review

Abstract. Recurrent aphthous stomatitis (RAS) and herpes labialis (HL) are among the most common recurrent oral mucosal conditions encountered in general dental practice, and are frequently confused by patients despite distinct etiologies, clinical presentations, and management pathways. RAS affects up to one quarter of the general population and is characterized by painful, non-keratinized mucosal ulcers of multifactorial etiology involving genetic predisposition, local trauma, hematinic deficiency, and a T-cell-mediated immunologic reaction. HL results from reactivation of latent herpes simplex virus type 1 (HSV-1), acquired in the majority of the population during childhood, and presents as clustered vesicular lesions of the keratinized lip and perioral skin. This review summarizes current evidence on the epidemiology, etiology and pathogenesis, diagnostic approach, and management of both conditions, with attention to features that aid differential diagnosis in clinical practice.

Epidemiology

Recurrent aphthous stomatitis is one of the most prevalent oral mucosal diseases, affecting approximately 20% to 25% of the general population, with onset typically in the first or second decade of life.¹ Of the three recognized clinical subtypes, minor aphthous ulcers account for roughly 80% of cases, while major and herpetiform variants are comparatively uncommon.¹ A family history is reported by 24% to 46% of RAS patients, and those with a positive family history tend to develop more severe and earlier-onset disease.^1,2

Herpes labialis is similarly widespread: HSV-1 seroprevalence reaches well over half of adults in most populations, with primary infection usually acquired asymptomatically or subclinically in childhood through non-sexual contact such as shared utensils or caregiver kissing.³ Following primary infection, an estimated 20% to 40% of seropositive individuals go on to experience recurrent symptomatic reactivation at the lip and perioral skin.³

Etiology and Pathogenesis

Recurrent aphthous stomatitis. The etiology of RAS remains incompletely understood and is considered multifactorial. Histopathologically, a T-cell-mediated immunologic reaction precedes ulceration: mononuclear cell infiltration and keratinocyte vacuolization produce localized epithelial breakdown, with tumor necrosis factor-alpha (TNF-α) implicated as a key inflammatory mediator driving neutrophil chemotaxis and CD8+ T-cell–mediated epithelial destruction.^1,4 Recognized local and systemic predisposing factors include local mucosal trauma, psychological stress, hormonal fluctuation, hematinic deficiencies (iron, folate, vitamin B12), and cessation of smoking.¹ RAS is also associated with systemic conditions including Behçet disease, inflammatory bowel disease, celiac disease, and HIV infection, and atypically severe or adult-onset presentations warrant screening for these associations.^1,4

Herpes labialis. HL is caused by HSV-1, a double-stranded DNA virus that establishes latency in the trigeminal ganglion following primary mucocutaneous infection. Reactivation is triggered by a range of stimuli including psychological stress, ultraviolet light exposure, febrile illness, hormonal changes (including menstruation), local tissue trauma, and immunosuppression; reactivated virus travels anterogradely along the sensory nerve to produce recurrent vesicular lesions at or near the original inoculation site.³ Unlike RAS, HL is an infectious, contagious process, and viral shedding occurs both during symptomatic outbreaks and, less commonly, during asymptomatic periods.³

Diagnosis and Differential Diagnosis

Both conditions are typically diagnosed clinically. RAS presents as round or oval ulcers with a yellow-gray fibrinopurulent base and an erythematous halo, confined to non-keratinized mucosa (buccal and labial mucosa, ventral tongue, floor of mouth); lesions on keratinized mucosa (hard palate, attached gingiva) should prompt reconsideration of the diagnosis.¹ HL, by contrast, characteristically involves keratinized lip vermilion and perioral skin, beginning with a prodromal tingling or burning sensation followed by clustered vesicles on an erythematous base that rupture and crust within 24 to 48 hours.³

Differential diagnosis for RAS includes Behçet disease (concurrent genital ulceration, uveitis, skin lesions), PFAPA syndrome in children, cyclic neutropenia, and HIV-associated aphthous ulceration; a sudden change in ulcer pattern in an adult, or ulcers accompanied by systemic symptoms, warrants laboratory evaluation including complete blood count and hematinic studies.^1,5 When the clinical picture is ambiguous, viral culture, polymerase chain reaction, direct fluorescent antibody testing, or Tzanck smear can confirm HSV-1 infection.³

Management

Recurrent aphthous stomatitis. There is no curative treatment for RAS; management is directed at symptom control, reduction in ulcer duration and severity, and extension of disease-free intervals.^1,5 Topical corticosteroids, often combined with chlorhexidine gluconate mouthrinse, represent first-line therapy for mild to moderate disease, and are most effective when applied during the prodromal phase.^1,5 Commonly used topical agents include triamcinolone acetonide 0.1% in Orabase and high-potency agents such as clobetasol or fluocinonide for recalcitrant lesions.¹ Short courses of systemic corticosteroids are reserved for major aphthous ulcers or disease significantly impairing oral intake, and immunosuppressive agents (e.g., colchicine, pentoxifylline) may be considered for severe, continuous disease under specialist supervision.¹ Correction of identified hematinic deficiencies is indicated where present, though supplementation does not reliably resolve ulceration in all patients.¹

Herpes labialis. Oral antivirals — acyclovir, valacyclovir, and famciclovir — are effective for treating acute recurrences and are most beneficial when initiated at the first sign of prodrome.³ Suppressive daily antiviral therapy can reduce recurrence frequency in patients with frequent outbreaks. Topical antivirals (acyclovir, penciclovir) and topical docosanol are available over the counter but are generally less effective than systemic therapy.³ Patients should be counseled on contagion precautions during active lesions, including avoiding direct contact and shared personal items, particularly around immunocompromised individuals, neonates, and patients with atopic dermatitis at risk for eczema herpeticum.³

Clinical Takeaways

Correctly distinguishing RAS from HL at initial presentation guides appropriate therapy and patient counseling, and atypical presentations of either condition — unusually large or persistent ulcers, systemic symptoms, or lesions in immunocompromised patients — warrant further work-up. A patient-oriented companion to this review, covering practical differentiation and home care guidance, is available in our guide to canker sores versus cold sores. Routine oral mucosal screening is incorporated into our preventive care program.

References

1. Plewa MC, Chatterjee K. Recurrent Aphthous Stomatitis. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Nov 13.
2. Slebioda Z, Szponar E, Kowalska A. Etiopathogenesis of recurrent aphthous stomatitis and the role of immunologic aspects: literature review. Arch Immunol Ther Exp (Warsz). 2014;62(3):205-215.
3. Panda S, et al. A Comprehensive Overview of Epidemiology, Pathogenesis and the Management of Herpes Labialis. Viruses. 2023;15(1):225.
4. Edgar NR, Saleh D, Miller RA. Recurrent Aphthous Stomatitis: A Review. J Clin Aesthet Dermatol. 2017;10(3):26-36.
5. Milia E, Sotgiu MA, Spano G, Filigheddu E, Gallusi G, Campanella V. Recurrent aphthous stomatitis (RAS): guideline for differential diagnosis and management. Eur J Paediatr Dent. 2022;23(1):73-78.

This article is provided for educational purposes for dental professionals and interested patients. It is not a substitute for individualized clinical judgment or professional dental care. Patients with persistent, atypical, or systemically associated oral ulceration should seek evaluation from a qualified dental or medical professional.