Lichen planus evoked by periodontal surgery.

A case of Lichen Planus (LP) following periodontal surgery in a patient previously free of the disease is described. Genetic predisposition and lymphokine secretion stimulated by local trauma are suggested as a possible mechanism of the phenomenon. It is recommended that LP patients, especially those suffering from the erosive type, should be treated as conservatively as possible, minimizing the possibility of trauma to the oral tissues where local immunity may have been altered by a pathological process.