A clinical and histopathological study of pityriasis lichenoides.

BACKGROUND Pityriasis lichenoides is a papulosquamous disorder of unknown etiology with remissions and exacerbations. Histopathology helps greatly in the diagnosis of this condition. AIM We studied clinical and histopathological features of pityriasis lichenoides in our patients. METHODS This is a 3-year retrospective and prospective, descriptive study of all patients clinically diagnosed as pityriasis lichenoides and confirmed by histopathology. All patients were studied clinically and histopathologically. RESULTS There were 51 (30 males and 21 females) cases of pityriasis lichenoides in the study period. The maximum number of cases, 14 (27.45%) were in their second decade of life. Pityriasis lichenoides chronica was diagnosed in 39 cases (76.47%) and pityriasis lichenoides et varioliformis acuta (PLEVA) in 12 cases (23.53%). Histopathologically, basal cell vacuolation and perivascular infiltrate were seen in all the cases. Exocytosis was seen in 45.1% of the cases. All the cases of PLEVA showed lymphocytic vasculitis albeit without fibrinoid deposition in the vessel walls. CONCLUSION Pityriasis lichenoides is not a rare disorder, and is not a true lymphocytic vasculitis as blood vessel damage and fibrinoid deposition in the blood vessel walls were not seen in this study.