ORAL LICHEN PLANUS – CLINICAL FEATURES,HISTOPATHOLOGY AND TREATMENT
Author: Sanketh DS, MDS
Lichens are primitive plants composed of algae and fungi. Planus means flat in Latin. Erasmus Wilson coined this term, probably because he thought the lesion was similar to the lichens growing on rocks.
Lichen planus is chronic muco-cutaneous disease of auto-immune origin, affecting around 0.2 – 2 % of the population. It could appear in the skin, in the oral mucosa or sometimes both. Oral lichen planus(OLP) could either accompany the cutaneous/skin lesions or precede them.
Stress and anxiety are known to be significant factors in inducing this condition. There are reports, however, stating that this could be anecdotal and that it lacks enough evidence.
Reports of an association with Hepatitis C have appeared in literature, usually from the Mediterranean countries, but more recent epidemiological studies do not support this association.
A variety of drugs and other foreign bodies may elicit a host response to induce these lesions in the oral cavity, but these type of lesions are better designated as lichenoid mucositis or lichenoid lesions.
Ultimately no one yet knows what causes this disease and it is generally considered to be auto-immune in nature.
Most patients of OLP are middle aged with a male: female ratio of 2:3.
OLP manifests in a variety of clinical variations: reticular, atrophic/erythematous, erosive/ulcerative, plaque/hypertrophic type and bullous type.
Is the most common type, manifesting frequently in the buccal mucosa bilaterally and symmetrically, and also occasionally on the tongue, gingiva and lips. It is characterised by numerous interlacing white keratotic lines or striae called Wickham’s striae. Is usually asymptomatic or presents with minimum clinical symptoms.
This form of the disease usually presents as red patches in conjunction with reticular striae and with the erosive variant. Patient may complain of burning sensation and discomfort. This manifestation of the lesion usually appears on the gingiva producing a pattern called desquamative gingivitis. But this term is not strictly reserved for OLP and is rather a vague,broad clinical term that includes other conditions like Pemphigus vulgaris, Cicatricial pemphigoid, Epidermolysis bullosa and linear IgA disease.It also frequently occurs on the buccal mucosa.
This form of OLP manifests with an ulcer covered with pseudomembranous exudate associated with reticular striae and also erythematous patches. Patients may complain of a sore mouth and difficulty in mastication.
White raised or flat plaques may occur as a variant of the lesion usually on the tongue and buccal mucosa. This form of OLP is difficult to distinguish from leukoplakia. It may occur in conjunction with a white striae and may be an irregular to smooth plaque, often involving more than one area of the affected site.
In people of colour, patchy areas of reactive melanosis may develop in the lesions, due to stimulation of the melanocytes by the inflammatory cells.
The features of the reticular and the plaque type OLP are areas of epithelial hyperkeratosis with focal areas of atrophic epithelium in between. There may be acanthosis of the spinous layer with pointed saw-tooth rete pegs. The immediate adjacent connective tissue consists of a band of dense layer of inflammatory cells composed of T-lymphocytes obscuring and degrading the basement membrane and infiltrating the epithelium.
The erosive and atrophic forms have the same features under the microscope, except that the epithelium is relatively thinned and destroyed by the inflammatory cells.
The microscopic diagnosis can be aided by immunofluorescence where it would be positive for fibrinogen and negative for IgA, IgM and IgG antibodies.
Clinically it becomes very important to differentiate OLP from other lesions because OLP is classified as a disease that could sometimes progress to become malignant.
The plaque type may be difficult to distinguish from leukoplakia.
HOW COULD ONE DIAGNOSE OLP?
Remember that the bilateral reticular pattern on the buccal mucosa are characteristic.
Even if it manifests as other variants, look for focal areas of white striae.
If there are isolated OLP like lesions on sites like the ventral surface of tongue, soft palate or the floor of the mouth, a biopsy is recommended to rule out any malignant changes.
These are 2 sets of criteria used to diagnose OLP. One was proposed in 1978 by the WHO and the other set of guidelines were put forth by van der Meij and associates in the year 2003. Criteria proposed in 2003 were essentially modified from the previous WHO set of guidelines. Whether one set of guidelines is more accurate than the other is debatable,but there have been studies,stating 2003 guidelines to have less of a subjective bias.
Corticosteroids are the most useful group of drugs in the management of oral lichen planus.
Topical application of corticosteroids like Triamcinolone acetonide, betamethasone, clobestosol could be effective in inducing healing within a week or two. However, the patient must be informed of a potential flare up, when the topical application is stopped.
Antifungal therapy along with topical corticosteroids may enhance clinical results due to elimination of secondary colonization of candida in OLP sites.
Systemic topical Vitamin A analogs (retinoids) have also been used with varied degree of success.
Patients must be kept under routine follow-up, due to the potentially malignant nature of OLP and good oral hygiene and avoidance of tobacco or alcohol habits are to be maintained.
Rajendran R, Sivapathasundaram B. Shafer’s Textbook of Oral Pathology. 6 th ed. Elsevier; 2008.
Neville BW, Damm DD, Allen CM, Chi A. Oral and Maxillofacial Pathology. South Asian ed. Elsevier; 2016.
Regezzi JA, Sciubba JJ, Jordan RCK. Oral Pathology: Clinical Pathologic Correlations. 5 th ed. Elsevier; 2007.
Sapp JP, Eversole LR, Wysocki GP. Contemporary Oral and Maxillofacial Pathology. 2 nd ed. Mosby; 2004.
Van der Meij EH, van der Waal I. Lack of clinicopathologic correlation in the diagnosis of oral lichen planus based on the presently available diagnostic criteria and suggestions for modifications. J Oral Pathol Med 2003;32:501-512.
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