Evaluation of leishmanin skin test and its relationship with the clinical form and duration of cutaneous leishmaniasis.

Background: Cellular immunity plays a major role in natural defense against cutaneous leishmaniasis. The leishmanin skin test (LST) is one method of evaluating the infected individual's immune response to leishmania. Our objective in this study was to evaluate the relationship between positivity of the LST with duration of disease, clinical form, number of lesions, and age and gender of the patient.

Materials And Methods: This open study was performed on 198 patients who were affected by cutaneous leishmaniasis before any treatment was administered. Following confirmation of the diagnosis of cutaneous leishmaniasis, relevant data were recorded, including age, gender, occupation, address, duration of disease, clinical form, location of the lesions, and the number of the lesions. After performing the leishmanin skin test, patients were treated for leishmaniasis according to the type and severity of the disease. For patients whose LST was initially negative, the test was repeated every 15 days. If the LST was still negative after 4 months, the test was repeated every 3 months; if the LST remained negative 12 months after the first test, the result was considered negative. The collected data were statistically analyzed using the SPSS program.

Results: In 179 patients (90.4%) the test was positive at the time of the first test. In 7 patients (3.8%) it became positive during treatment, and in 12 patients (6 percent) the test remained negative until the end of study. There was no significant relationship between the skin lesion number and the positivity of the leishmanin skin test (p = 0.98). There was no significant relationship between age group and diameter of the induration. All of the patients who had negative leishmnanin test at the 12 months followup visit had one lesion only.

Conclusion: This study showed that there is no relationship between age, gender, or duration of disease with positivity of the LST or degree of positivity, but there is a significant relationship with the clinical form of cutaneous leishmaniasis at the final test (12 patients). This study showed that there is no significant relationship between positivity of LST and the type of treatment.