The relation between toxoplasmosis and pityriasis lichenoides chronica

Pityriasis lichenoides chronica (PLC) is a rare skin disease of uncertain aetiology. Many infectious agents have been incriminated as the cause of the disease. One of these agents is toxoplasmosis. The aim of this work was to find out if there is a relationship between toxoplasmosis and PLC. Twenty two patients (17 males and 5 females) diagnosed clinically and histopathologically as PLC were chosen for this study. Also twenty apparently healthy individuals free from skin lesions were included as a control group. Patients and controls were examined clinically for signs of toxoplasmosis and submitted for indirect haemagglutination (IHA) and indirect immunofluorescent antibody (IFA) tests in our Parasitology laboratory for serodiagnosis of toxoplasmosis. Toxoplasmosis was diagnosed in 8 (36.36%) and 3 (15%) in PLC patients and controls respectively by both tests. Using pyrimethamine and trisulfapyrimidine in treating PLC patients, showed subsidence of skin lesions in five patients with toxoplasmosis within two months from the beginning of therapy. The remaining patients showed no response to treatment. On conclusion, toxoplasmosis appears to play a role in the aetiology of PLC and serological tests for diagnosing toxoplasmosis should be performed in all PLC patients.