Smoking habits of 611 patients with oral lichen planus.

The smoking habits of 611 patients (68 per cent females and 32 per cent males) with oral lichen planus were studied. Forty-six per cent were daily smokers, 4 per cent smoked only at social events, and 50 per cent were nonsmokers. In comparison with the nonsmokers, the daily smokers showed significantly lower prevalences of reticular and atrophic types of oral lichen planus lesions and a significantly higher prevelance of the plaque type (P less than 0.001). It is suggested that these findings depend on a mechanism whereby original atrophic and reticular types of lesions are altered into the plaque type of lesions under the influence of smoking. The question arises whether such plaque type of lesion can be regarded as leukoplakias which have been superimposed on the oral mucosa affected by lichen planus.