THE DEVELOPMENT of immunity to superinfection with Oriental sore is delayed until parasites are no longer found in the primary lesion. In general, patients recovering from Oriental sore remain immune for life, after total cicatrization of the site of the primary infection. In a certain number of cases, however, relapse lesions may develop at the periphery of the primary scar, within the scar, or at some distant site. Thus, among 600 patients treated for Oriental sore at the Hadassah dermatological outpatient department in Jerusalem, approximately 10% were relapse patients.
The leishmanin test, an allergic skin reaction analogous to the tuberculin test, has proved to be a reliable indication of previous exposure to Leishmania tropica.1 Sagher2 has shown that the degree of sensitivity to leishmanin is greater in patients with leishmaniasis recidiva (relapsing cutaneous lesions) than in those with leishmaniasis nodosa (primary cutaneous lesions), since positive tests
DOSTROVSKY A, SAGHER F, ZUCKERMAN A. ISOPHASIC REACTION FOLLOWING EXPERIMENTAL SUPERINFECTION OF LEISHMANIA TROPICA. AMA Arch Derm Syphilol. 1952;66(6):665–675. doi:10.1001/archderm.1952.01530310003001