Three cases of 'morsicatio labiorum'.

Morsicatio labiorum is a form of tissue alteration caused by self-induced injury, mostly occurring on the lips, and is considered to be a rarely encountered mucocutaneous disorder. Clinically, it is a macerated grey-white patch and plaque of the mucosa caused by external stimuli (self-induced injury) such as habitual biting, chewing, or sucking of the lip. It is often confused with other dermatological disorders involving the oral mucosa, which can lead to a misdiagnosis. We herein report three cases of morsicatio labiorum; two cases were misdiagnosed as exfoliative cheilitis at the time of the first visit.