Oral Lichen Planus

Oral lichen planus is a common chronic inflammatory mucocutaneous disorder that typically affects the skin and/or mouth. Lichen planus can also affect other non-oral mucosal surfaces such as the genitals anus and pharynx, and rarely the conjunctiva and oesophagus.

Oral lichen planus has a bilateral distribution that typically affects the buccal mucosa, dorsum and ventral surfaces of the tongue and/or gingiva. Other mucosal surfaces can be affected but palatal involvement is particularly rare.

Oral lichen planus is often asymptomatic, although when there are areas of erosion or ulceration, the patient may have variable amounts of discomfort, being particularly troublesome when eating spicy or acidic type foods.

The variable clinical presentations of oral lichen planus comprise white patches, erosions, ulcers and, very rarely, blisters. The classification of the clinical presentation of lichen planus can be split into the following:

• Reticular oral lichen planus – this is the most common presentation, manifesting as a network of white striations. These lesions are often painless, although patients may complain of a slight roughness or dryness to the affected mucosal surfaces.
• Plaque-like oral lichen planus – this manifests as areas of homogenous whiteness. This typically arises on the buccal mucosa or dorsum of tongue and may be more prevalent amongst those who are smokers.
• Papular oral lichen planus – this manifests as small white raised areas approximately 1-2mm in diameter. These again typically arise on the buccal mucosa and dorsum of tongue, although may also present on other mucosal surfaces.
• Erosive oral lichen planus – this is sometimes termed atrophic oral lichen planus. In this form there are areas of redness within the aforementioned white patches. Patients with this type of disease often complain of oral soreness
• Ulcerative lichen planus – there are frank ulcers within the areas of whiteness. Patients complain of continued soreness, this being particularly severe with spicy or acidic foods.
• Bullous lichen planus – this rare presentation manifests as small vesicles or blisters (bullae) within the white patches.

Patients with disease involving the gingiva may have areas of white patches or striae superimposed upon redness of the gums. The latter is often termed desquamative gingivitis and can be extremely painful.

There is little predictability as regards the frequency of non-oral disease in patients with oral lichen planus. Likewise the oral features may precede, accompany or follow lichen planus affecting other sites.

It is believed that oral lichen planus represents a cell-mediated immunological reaction within the affected tissues. The precise trigger for this is not known. The precise cause of oral lichen planus remains unclear in most cases.

Some patients appear to have an identifiable precipitating factor, and these are often termed lichenoid reactions. Occasional patients may have isolated areas of lichenoid reactions adjacent to amalgam restorations. Similar observations have been reported with dental restorations made of other metallic and non-metallic materials.

A small minority of patients may have lichenoid reactions that arise following drug therapy – particularly non-steroidal anti-inflammatory agents, beta-blockers, sulphonylureas, gold, penicillamine, allopurinol and occasionally anti-malarials. Lichenoid reactions can arise in patients who have chronic graft-versus-host disease subsequent to bone marrow transplantation.

It has been suggested, but remains unclear, that there has been associations between oral lichen planus and hepatitis C virus infection. This association appears to occur more often in individuals living in areas of southern Europe, particularly Portugal, Spain and Italy. An association between hepatitis C virus infection and oral lichen planus has also been observed in individuals resident in Japan. Such associations may be related to the carriage rates of Hepatitis C in these parts of the world, or reflect some genetic predisposition to HCV-related oral lichen planus.

Patients with white patches are generally asymptomatic, although they may complain of mild oral roughness, soreness or dryness of the oral mucosa. This generally does not require treatment. Individuals with erosive, ulcerative or bullous disease generally tend to have oral discomfort, particularly with spicy or acidic foods, and thus require treatment.

The management of painful oral lichen planus usually comprises:

• Relief of painful symptoms – this can best be achieved with regular use of benzydamine hydrochloride (0.15%) spray or mouthrinse. When this is not available, it may be appropriate for the patient to apply 2% lidocaine gel to painful areas; •
• Treatment of definitive disease – topical corticosteroids are the mainstay of treatment of oral lichen planus. A wide range of agents are suggested to be effective . These include:
  • Triamcinolone acetonide (0.1%) and 1% carboxymethylcellulose paste
  • Betamethasone mouthrinse (500mcg dissolved in 10-15ml of water) used as a mouthrinse up to 3 times daily
  • Fluticasone spray (50mcg per puff) – sprayed on affected areas up to 3-4 times daily
  • Prednisolone mouthwash (5mg dissolved in 10-15ml of water) and used as a mouthrinse up to 4 times daily
  • Beclometasone spray (100mcg per puff) – sprayed 3-4 times daily on affected sites
  • Clobetasol ointment (0.05%) applied to painful areas 3-4 times daily
  • Fluticasone cream (0.05%) applied to painful sites 3-4 times daily

Where disease appears to be recalcitrant to such therapy, a number of other strategies may be considered:

• • Topical tacrolimus (0.1%) applied to painful areas twice daily
  • Ciclosporin mouthwash (100mg per ml) used as a swill and spit mouthwash twice daily

Severe disease may warrant short-term systemic corticosteroid therapy (e.g. prednisolone or deflazacort), with additional corticosteroid-sparing immunosuppressant regimes such as azathioprine. Patients with symptomatology affecting other mucosal surfaces or the skin require referral to appropriate specialist for further evaluation.

At the present time, as the cause of lichen planus is unknown, there is no specific preventative programme for this disorder. Likewise there remains no evidence that modification of diet or oral hygiene will lessen the possible development of symptomatic disease. However, regular clinical review is important in view of the controversy regarding the malignant potential of this disorder.