To the Editor.—
The origin of lichen planus (LP) is still unknown. Recently we described a number of patients with LP who were found to have a carbohydrate metabolism disorder when they were subjected to a glucose tolerance test.1 At the same time, we incidentally noticed that many of these patients with LP also suffered from urolithiasis.Following this preliminary observation, a survey was carried out to find the frequency of occurrence of urolithiasis in a large group of patients with LP. This survey included 130 patients with LP (57 male and 73 female patients) who attended our outpatient dermatology clinic at the Beilinson Medical Center, Petah-Tiqva, Israel, between 1975 and 1981. From the anamnesis and medical records of these patients it was found that 19 (14.6%) had urolithiasis. Surveys taken in Israel during previous years2,3 showed the incidence of urolithiasis in the general population to be only 1.18%