Circuit 3, station 10

Lichen planus (LP) is a chronic, multi-system mucocutaneous disorder that affects the oral and genital mucous membranes as well as the skin, nails, and scalp. Oral lichen planus (OLP) is a T-cell mediated autoimmune disease in which apoptosis of the basal cells of the oral epithelium is triggered by the auto-cytotoxic CD8 + T cells. 

Clinical features of OLP

The cutaneous lesions of LP are characterised by 5mm, purple, polygonal, itchy papules and plaques.

In the oral cavity, the disease has a different appearance than that on the skin. The lesions are white or grey in colour, velvety in nature, thread-like papules which can either be linear, annular and retiform in arrangement forming reticular patches, streaks and rings. 

At the intersection of the white lines, a small elevated white dot can be present and is called a striae of Wickham.

The lesions can be asymptomatic, bilateral and/or symmetrical anywhere in the oral cavity. The most common locations are the: tongue, lips, mouth floor, buccal mucosa and palate. There can be a long lag time between the appearance of skin and oral lesions. 

6 types of OLP

• Reticular
  • Most common clinical form
  • Presents with Wickham striae bilaterally and symmetrically
  • Mostly affects the posterior mucosa of the cheek
• Plaque-like
  • Whitish homogeneous irregularities with a similar appearance to leukoplakia, and reticular are usually asymptomatic
  • Mostly affects the dorsum of the tongue and cheek mucosa
• Atrophic
  • Diffuse red lesions and can resemble the combination of two other clinical forms, e.g. Wickham striae of reticular type but surrounded by erythema. 
  • Usually where previous LP lesions were. 
• Erosive
  • Most severe form, with burning/discomforting lesions commonly surrounded by a network of fine radiant keratinized striae.
• Bullous
  • Has erosive, atrophic and bullous blisters, with a tendency to rupture and increase in size, resulting in painful ulcers. 
  • Nikolsky’s sign (i.e. rubbing skin slips away the top layer) may be positive.
• Papular
  • Rarest form, normally followed by some other type from above. 
  • Presents with small white papules with fine peripheral striae.

Risk factors for OLP

Drugs

Systemic drugs including:

• NSAIDs
• beta blockers
• Sulfonylureas
• angiotensin-converting enzyme (ACE) inhibitors
• some antimalarials 

contact allergens including certain toothpaste flavours, especially cinnamon

Autoimmune conditions

• diabetes mellitus
• primary biliary cirrhosis
• chronic active hepatitis
• ulcerative colitis
• myasthenia gravis
• thymoma

Anxiety and stress

Hypertension 

Viral infections

• Epstein Barr virus
• Varicella Zoster virus
• Human Herpes virus 6 and -7
• Human Papillomavirus
• Hepatitis C

And others. Dental materials that produce a lichenoid reaction are also a risk factor. The differentiation between a lichenoid reaction and OLP is whether it has resolved. If it resolves, it is a lichenoid reaction, if it does not, then it is OLP. Materials that have been found to cause OLP include gold, silver amalgam, cobalt, palladium, chromium, prolonged use of dentures and non-metal agents. 

Risks for malignant transformation

NICE and the WHO both state that OLP is a risk factor for the development of Oral squamous cell carcinoma (OSCC), which is the sixth leading malignancy worldwide. Average age of onset is 60-70 years old. The main risk factors for malignant transformation to OSCC are tobacco use and/or excess alcohol intake, immunosuppression drugs, certain viruses, chronic inflammation usually of systemic causes, and a poor diet without or having low levels of fresh fruits and vegetables.

Investigations

History with physical typical oral lesions and skin or nail involvement is usually enough for a clinical diagnosis of OLP. However, a biopsy is the recommended procedure to differentiate it from other lesions.

Differential diagnoses

• cheek chewing/frictional keratosis
• Leukoplakia
• lichenoid reactions (but if don’t resolve then OLP)
• lupus erythematous
• Pemphigus (for bullous)
• mucus membrane pemphigoid (for bullous)
• para neoplastic pemphigus
• erythematous candidiasis / chronic ulcerative stomatitis 
• Graft vs. host disease (in transplants)

Management

• Analgesia local and systemic for symptomatic relief
• Reduce cancer risk i.e. smoking cessation, remove offending medication agent etc
• Good oral hygiene
• Aloe vera gel has been found to be effective in topical relief
• Glucocorticosteroids either topically or systemically

Contraindications for glucocorticosteroids include allergy, stomach ulcer, infectious diseases such as tuberculosis and viral infections

Surgical excision is recommended for non-healing lesions as it can be curative, but is not recommended for atrophic / erosive OLP