Lichen Planus:

Lichen planus is a chronic disease of the skin and mucous membranes which is felt to be due to basal cell layer destruction by activated lymphocytes. Characteristic skin lesions include violaceous, pruritic papules over the flexor surfaces of the extremities and several types of oral lesions have been described, including reticular, papular, plaque, and atrophic (erosive), ulcerative, and bullous variations. Desquamative gingivitis can also frequently present as a manifestation of Oral Lichen Planus.

Reticular lichen planus shows fine, slightly raised, white or violaceous threadlike lesions in a ring like, lacy pattern (Wickman’s striae). These lesions are often located on the buccal mucosa. The hypertrophic form resembles leukoplakia as homogenous white plaques. Atrophic or erosive lichen planus present as erythematous shallow ulcers that, in contrast to most forms of lichen planus, may be painful. Histologically, lichen planus shows hyperkaratosis, “saw-tooth” rete ridges, liquefactive degeneration of the basal cell layer, and a band-like subepithelial inflammatory infiltrate. Discrete eosinophilic ovoid bodies (Civatte bodies) are occasionally seen in the basal cell layer. Treatment is symptomatic, the mainstay of therapy involves the use of either topical or systemic steroids. The use of other immunomodulatory agents is often necessary, these include Dapsone, Azathioprine, Cyclosporin and Tacrolimus. Mild cases usually do not require therapy. Topical steroids may be useful in controlling local symptoms and topical retinoids, with antikeratinizing effects, can be used for the plaque form. Dapsone has also been used for severe forms with some success.

Oral Lichen Planus - OLP

Aetiology

The aetiology of OLP is unclear, though there is clear evidence of a T lymphocyte attack on the stratified squamous epithelia. Usually no aetiological factor is identifiable but a minority of cases are related to:

Clinical Features

The oral lesions of OLP are usually:

Lesions are usually white and may be asymptomatic or may cause soreness, especially if erosive. Presentations include:

Lichen Planus may also affect

Management

The history and clinical appearance are usually highly indicative of the diagnosis but lesional biopsy is often indicated, particularly to exclude lupus erythematosus, leukoplakia (keratosis), or malignancy.

OLP is often persistent but is usually benign. Atrophic LP clinically closely resembles erythroplasia – a premalignant condition – but there is about a 1 to 3% chance of malignant transformation over 5 years, predominantly in those with long-standing erosive LP.

Systemic disease, drugs, or local possible predisposing factors (such as amalgam restorations) should be excluded. If drugs are implicated, a physician should be consulted as to possible changes in therapy. If amalgam restorations might be implicated, it may be worth considering replacing amalgams adjacent to lesions by an alternative restorative material. Unfortunately, skin patch testing for mercury hypersensitivity is not reliable in suggesting patients who might benefit from replacement of restorations. However, if lesions are in close relationship to a restoration, or are unilateral, or if an associated amalgam restoration is in need of repair, a replacement trial may be indicated.

Symptomatic OLP may respond to topical corticosteroids, and patients should be informed about the condition. Recalcitrant lesions can be managed with intralesional corticosteroids or topical cyclosporin. Systemic immunosuppressive agents, including corticosteroids, azathioprine, cyclosporin or dapsone – or, rarely, vitamin A derivatives such as etretinate – may be required but should be given only by a specialist in view of the serious adverse effects possible. If the GP is in any doubt about the diagnosis or management of OLP, then specialist referral is indicated

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Lichen planus on skin of wrist

Lichen planus affecting nails

Reticular lesion on cheek

OLP buccal sulcus

Lichen planus, retromolar

Lichen planus, reticular lesions

OLP side of tongue

OLP dorsum of tongue

OLP tongue, dorsum, centre

OLP plaques, tongue, dorsum

These images of oral pathology are copyright Dentalgain.org and Cork University Dental School and Hospital except where otherwise acknowledged.