The objective of this single center, 4-week, open label randomized, phase II study is to evaluate and characterize the tolerability and clinical effectiveness of dexamethasone 0.5mg/5ml solution in a mucoadhesive vehicle (Mucolox™) for the treatment of oral lichen planus.

Potentially eligible subjects will be screened by one of the investigators by asking patients to rate their worst oral pain or pain score (0-10) over the previous week (see Appendix). Those answering with at least a score of "7" (1/10) and that meet all other eligibility requirements (see Section 3) will be eligible for enrollment. All patients will sign informed consent for study participation. Each study visit is anticipated to take approximately 45 minutes.

Treatment will be administered on an outpatient basis. Study medication will be prescribed by authorized study staff physicians at no expense for the patient.

Subjects will be evaluated clinically at baseline before starting treatment and at the end of the four-week period, for a total of two visits. Comprehensive subjective and objective data will be collected and intraoral photographs will be obtained. Oral mucosal disease will be evaluated using both patient reported (questions/visual analog scales) and clinician assessed measures.

Subjects will be prescribed compound dexamethasone 0.5mg/5ml solution in Mucolox™ (ARM A) or dexamethasone 0.5mg/5ml solution only (ARM B). All subjects will also receive a prescription for fluconazole 200 mg tablets once-a-week as prophylactic antifungal therapy. Any subjects that are already taking an antifungal oral medication at the time of the study enrollment will continue their prescribed medication and will not need to take the additional weekly fluconazole dose. Subjects will return for evaluation after four weeks at which time the study end-points will be assessed.

If there is worsening of oral lichen planus that requires initiation of new immunomodulatory medications (systemic or topical), patients will remain on treatment, but will be regarded as unevaluable for the primary endpoint.

Inclusion Criteria:

• Age 18 years and older.
• Patients with symptomatic oral lichen planus (worst VAS sensitivity score ≥ 7 over the last week).

Exclusion Criteria:

• Patients already on topical or systemic steroids.
• Inability to comply with study instructions.
• Uncontrolled intercurrent illness or psychiatric illness/social situations that would limit compliance with study requirements.
• VAS sensitivity score < 7.

Onset of symptoms were reported 4-5 days after initiating the treatment and lasted 24h. The treatment was interrupted for 2 days and resumed thereafter with no recurrence or any other adverse event. The subject was monitored through study completion (4 weeks after baseline).

Abdominal discomfort 4-5 days after initiating study drug. Study drug was discontinued and event ended 2 days later and did not recur.