Oral Lichen Planus (OLP) is a chronic, inflammatory condition that affects the mucous membranes inside the mouth. It is considered an autoimmune disorder where the immune system mistakenly attacks the cells of the oral mucosa. OLP is of particular interest in dentistry because of its relatively common occurrence (approximately 1–2% of the population), its varied clinical presentation, its potential for causing significant discomfort, and its small but important potential for malignant transformation into oral squamous cell carcinoma.
Understanding OLP is crucial for any dental professional, as it requires a keen eye for diagnosis, careful management, and lifelong patient follow-up.
Etiology and Pathogenesis: Oral Lichen Planus (OLP)!
The exact cause of oral lichen planus remains unknown. However, it is widely accepted that it involves an abnormal T-cell-mediated immune response. In susceptible individuals, cytotoxic CD8+ T-cells are thought to induce apoptosis of basal keratinocytes of the oral epithelium, leading to the characteristic histopathological and clinical features.
Several factors are believed to trigger or exacerbate OLP, including:
- Genetic predisposition
- Stress and psychological factors
- Medications (e.g., NSAIDs, beta-blockers, antimalarials)
- Dental restorative materials (e.g., amalgam)
- Chronic infections (e.g., hepatitis C virus)
- Systemic diseases (e.g., diabetes, hypertension)
Despite these associations, in many cases, no clear causative agent can be identified.
Clinical Features: Oral Lichen Planus (OLP)
OLP typically affects adults between the ages of 30 and 60 years, with a higher prevalence among women (female-to-male ratio approximately 2:1). It is rare in children.
The clinical presentation can vary considerably. Six major clinical types are recognized:
- Reticular
- Most common form
- Characterized by interlacing white lines called Wickham’s striae
- Usually asymptomatic
- Commonly found on the buccal mucosa, but also the tongue and gingiva
- Erosive
- Ulcerated, painful lesions surrounded by peripheral white striae
- Patients often report burning or soreness, especially when eating spicy or acidic foods
- Higher risk of malignant transformation
- Atrophic
- Diffuse, erythematous areas with associated white striae
- Often affects the gingiva, resembling desquamative gingivitis
- Plaque-like
- White patch resembling leukoplakia
- Often seen on the dorsum of the tongue
- Papular
- Small white raised lesions, often coexisting with reticular patterns
- Bullous
- Blister formation, although true bullous OLP is rare
Distribution
- Bilateral and symmetrical lesions are characteristic.
- Common sites include buccal mucosa, tongue, gingiva, lips, and the floor of the mouth.
Histopathological Features : Oral Lichen Planus (OLP)
Histology is critical for definitive diagnosis. A biopsy typically shows:
- Hyperkeratosis (thickening of the keratin layer)
- Saw-tooth appearance of the rete pegs
- Basal cell degeneration
- Dense band-like infiltrate of lymphocytes immediately below the epithelium
- Presence of Civatte bodies (apoptotic keratinocytes)
Direct immunofluorescence (DIF) may show deposition of fibrinogen along the basement membrane zone, assisting in diagnosis.
Diagnosis
Diagnosis of OLP is based on a combination of clinical and histological findings. Key points include:
- Careful history taking (e.g., onset, symptoms, systemic illnesses, medications)
- Thorough clinical examination
- Incisional biopsy with histopathological and, if needed, immunofluorescent studies
- Elimination of other differential diagnoses such as leukoplakia, oral candidiasis, lupus erythematosus, pemphigoid, and pemphigus vulgaris.
The modified WHO diagnostic criteria suggest that a definitive diagnosis of OLP requires both typical clinical and histopathological features.
Differential Diagnosis
- Oral leukoplakia
- Oral candidiasis
- Discoid lupus erythematosus
- Mucous membrane pemphigoid
- Chronic ulcerative stomatitis
- Graft-versus-host disease (GVHD)
Management
There is no definitive cure for OLP; hence, the treatment goal is symptom control, reduction of inflammation, and regular monitoring for malignant transformation.
General Measures:
- Patient education about the chronic nature of the disease
- Elimination of local irritants (e.g., sharp teeth, ill-fitting dentures)
- Smoking and alcohol cessation
- Stress management techniques
Pharmacological Therapy:
- Topical corticosteroids (first-line treatment)
- Examples: Fluocinonide 0.05% gel, Clobetasol propionate
- Application 2–4 times daily
- Systemic corticosteroids
- Reserved for severe, widespread, or refractory cases
- Short courses to minimize side effects
- Other immunosuppressive agents
- Topical calcineurin inhibitors (e.g., tacrolimus, pimecrolimus)
- Systemic agents like azathioprine, mycophenolate mofetil in difficult cases
- Adjunctive therapies
- Antifungal treatment to prevent or manage secondary candidiasis
- Analgesics for pain control
Non-Pharmacological Approaches:
- Low-level laser therapy (LLLT)
- Photodynamic therapy (PDT)
- Platelet-rich plasma (PRP) injections (emerging therapies)
Prognosis and Malignant Potential
Oral Lichen Planus is considered a potentially malignant disorder. The reported rate of malignant transformation varies widely, but recent meta-analyses suggest it is around 1–2%. Risk factors for transformation include:
- Erosive or atrophic forms
- Tongue lesions
- Long-standing, non-resolving disease
- Presence of dysplasia on histology
- Tobacco and alcohol use
Thus, long-term follow-up with regular clinical examinations (at least every 6–12 months) is essential. Any suspicious changes, such as persistent ulcers, induration, or changes in lesion appearance, warrant re-biopsy.
Oral Lichen Planus is a significant chronic mucosal condition that dentists must be equipped to recognize, diagnose, and manage effectively. Although it often remains stable or only mildly symptomatic, certain forms can cause considerable discomfort and carry a risk of malignancy. Proper patient education, careful monitoring, appropriate therapeutic interventions, and interdisciplinary collaboration with oral medicine specialists or dermatologists when necessary are critical components of comprehensive care.
Remember: while OLP may appear benign initially, its potential complications demand vigilant observation and patient-centered management throughout the patient’s life.