Oral Lichen Planus: Etiopathogenic, Clinical, Histopathological and Treatment Considerations

Abstract

Oral lichen planus (OLP) is a chronic autoimmune disease characterized by type IV hypersensitivity, which manifests as a cell response to antigen changes that occur in the lining oral mucosa. Among patients affected by this systemic disease, 25% only have lesions in the mouth and 50% simultaneously exhibit lesions in the oral mucosa and on the skin. Oral lichen planus is more common in adult middle-aged women in their 5th and 6th decades of life. The lesions are usually bilateral, symmetrical and multifocal, and the buccal mucosa is the most commonly affected site. Six clinical forms of OLP have been described, which usually coexist: reticular, papular, plaque-like, atrophic, erosive, and bullous. In 2005, the World Health Organization classified OLP as a potentially malignant disorder. However, there is still much controversy about this classification. Several epidemiological, retrospective and prospective studies conducted over the last 20 years in different parts of the world suggest the probability of a lesion initially diagnosed as OLP to progress to squamous cell carcinoma to be 0.65 to 1.9%. Nevertheless, some authors highlight the difficulty in diagnosing OLP. Others report the lack of a universal and specific standard method for the diagnosis of this disease, which can often be confused with lesions of epithelial cell atypias exhibiting a lichenoid appearance. Hence, clinical and histopathological criteria need to be taken into consideration for the diagnosis of OLP. There is no specific treatment. Oral lichen planus should be treated when the patient manifests symptoms, since no standardized management exists that is completely satisfactory and definitive. Since most patients do not complain of symptoms, periodical follow-up for reassessment of the lesions should be performed. Moreover, the erosive and atrophic forms are almost always symptomatic and professional follow-up at shorter intervals is necessary in these cases. Corticosteroids are the most widely used drugs for the management of symptomatic lesions.