EVEN IN a moderate climate, lichen planus presents a variegated appearance, although it usually is associated with well defined primary efflorescences. In subtropical regions, however, if a physician sees lichen planus during its further development, he meets manifestations which, although presenting a specific picture, may show such a degree of variation that dermatologists from elsewhere would be unable to make a correct diagnosis. GENERAL CONSIDERATIONS In this paper, a special form of lichen planus will be described. This type of the disease, which occurs in the Middle East, particularly in Palestine, offers new problems in many respects. The studies are based on the entire number of patients with the disease seen at the Dermatological Outpatient Department of the Rothschild-Hadassah University Hospital, Jerusalem, since the year 1930. Approximately half of the patients visiting the clinic are Jews of European extraction; the other half are Jews from oriental countries, who have, as