Lichen Planus Overview and Implications

Lichen Planus (LP)

• Definition:
  • Inflammatory autoimmune disease with no defined autoantibodies.
  • Chronic mucocutaneous disease affecting oral mucosa and skin.
• Malignant Transformation Rate:
  • 0.4%-3.3%.
• Etiology:
  • Autoimmune inflammatory: T-cells infiltrate and destroy epithelium. Inflammatory infiltrate attacks mucosal tissues, the exact cause remains unknown.
  • Contributing factors: genetics, stress (exacerbates, not causes), infections (e.g., Hepatitis C), or medications.
• Risk Factors:
  • Women over 40.
  • Other autoimmune diseases (e.g., IBS, DM, Lupus).
  • Infections (e.g., Hepatitis C).
  • Psychological stress.
• Prevalence:
  • ~65% in women over 40.
  • ~1% in general population.
• Types:
  • Reticular: Asymptomatic, white patches/thread-like lesions (Wickham's striae) on buccal mucosa, most common, possibly dysplastic.
  • Plaque-like: Dense thickening of mucosal tissue.
  • Erosive: Ulcerations, yellow-white fibrin slough with erythematous halo, affecting buccal mucosa, tongue, and labial mucosa. May mask Wickham's striae patterns.
  • Atrophic (Desquamative gingivitis): Bright red due to top layer loss, discomfort with spicy foods, associated with MMP and Pemphigus Vulgaris.
  • Bullous: Blisters on typical LP lesions, rare, more common on skin.
• Clinical Presentation (Oral Mucosa):
  • Bilateral and symmetrical lesions, usually multiple.
  • Lesions can be red or white, or both.
  • Persistent with remission and flare-ups.
  • Symptoms or asymptomatic depending on type.
  • Wickham's striae: White, lacy striae with redness on buccal mucosa.
  • Papules or plaques on buccal mucosa.
  • Painful sores.
  • Gingival involvement: desquamative gingivitis.
  • Common sites: buccal mucosa, tongue dorsum, gingivae.
• Clinical Presentation (Skin):
  • Itchy, purple papules, particularly on flexor regions (e.g., shins, wrists).
  • Koebner phenomenon: New lesions form at sites of skin injury.
  • Nail ridging.
  • Hair loss.
• Diagnosis:
  • History, clinical exam (risk factors, bilateral symmetry).
  • Rule out differentials (e.g., swab/smear for Candida, Nikolsky sign for pemphigus, systemic causes via FBC, Iron/Folate/B12 levels, Hepatitis C antibodies, Anti-nuclear antibodies (ANA), Anti-dsDNA for Lupus).
  • Biopsy (gold standard).
• Treatment:
  • Trigger avoidance (spicy foods, stress management).
  • Oral hygiene maintenance (especially for desquamative gingivitis).
  • Mouth lubrication.
  • SLS-free toothpaste.
  • Chlorhexidine 0.2%.
  • Symptomatic relief (e.g., benzydamine hydrochloride spray; 0.15% concentration).
  • Topical steroids (e.g., beclomethasone, betamethasone, hydrocortisone).
  • Topical immunosuppressants (e.g., cyclosporine mouthwash).
  • Systemic immunosuppressants (e.g., prednisolone, azathioprine) for severe cases.
  • Regular review (monitor for malignant transformation).
• Healing:
  • Can take 1-2 years.

Lichenoid Reactions (LR)

• Definition:
  • Type IV hypersensitivity reaction to a chemical agent or material. T-cell-mediated responses to antigen.
• Pathogenesis:
  • T-cells react to antigen and attack epithelium.
  • Resolution after removal of offending agent.
• Causes:
  • Materials (e.g., amalgam, nickel, bis-GMA).
  • Drugs (e.g., antihypertensives, NSAIDs, antimalarials, metformin, diuretics, including hydrochlorothiazide (HCTZ), furosemide, and spironolactone).
• Drugs specifically associated:
  • Ibuprofen, Naproxen (NSAIDs).
  • Beta-blockers (Propranolol, Metoprolol).
  • ACE Inhibitors (Lisinopril, Enalapril).
  • Oral Hypoglycemics (Metformin, Sulfonylureas).
  • Antimalarials (Chloroquine, Hydroxychloroquine).
• Clinical Presentation:
  • Similar to LP, but often unilateral, asymmetrical. May involve the palate.
• LP vs. LR:
  • Similar histology. LR has a known antigenic (trigger) cause, while LP does not.
• Diagnosis:
  • Patch testing (for LR).
• Management:
  • Remove cause.
  • Medication changes.
  • Material changes (e.g., denture bases, consider Valplast (Nylon)).
  • Treat as LP if no other cause found.
• Healing Time:
  • Ranges from 3-8 months.