An association between lichen planus and diabetes mellitus has been speculated for many years. In order to assess this potential problem, fasting plasma glucose levels and glucose tolerance test were studied in 50 patients with lichen planus and in 50 sex, age, matched healthy control subject. Abnormal GTT was observed in 14% of the patients and in 6% of the control group, overt diabetes mellitus was observed in 4% of the patients and in 2% of the control group. There was no statistically significant differences between this two groups.

Between, patients with abnormal GTT only one patient had not mucosal involvement. There was a significant difference in 120 minutes GTT of patients with mucosal and mucocutaneous lichen planus, when compared with cutaneous lichen planus. This was a statistically significant differences. (p < 0.05).