Introduction: Oral lichen planus is an autoimmune inflammatory disease. These clinical manifestations can sometimes be confused and cumulated with clinical signs of periodontal disorders. The aim of this work is to illustrate the interest of a periodontal follow-up in the management of oral lichen planus by a clinical case report. Observation: A patient came for a consultation in dermatology for a persistent gingival erythema. The diagnosis of oral lichen planus was made and treatments were successively implemented. After six months of follow-up, an inflammatory gum was still present without showing improvement. A stage 3, grade B periodontitis associated with oral lichen planus was diagnosed and a periodontal treatment was initiated, combined with corticosteroids treatment as mouthwash. Four months after the beginning of this treatment, a marked decrease in gingival erythema was observed. Comments: There is often a close relationship between oral lichen planus and periodontal disease therefore a multidisciplinary approach can be very useful for optimal management.