A Clinico-Pathological Study of Poly Morphous Light Eruption

Abstract

The prevalence of PMLE varies from 5% to 15% in various studies across the world. PMLE is noticed in the first three decades of life. The mean age in females is 33 years whereas in males it is 35 years. Females are more often affected than males. PMLE appears to be an immunologically mediated response possibly a delayed hypersensitivity phenomenon to a photo antigen induced or up regulated in the skin after sun exposure. One hundred new PMLE cases were included in a two year period from 2006-8. All patients, who had been on treatment and with concomitant dermatoses were excluded. On histo-pathological examination 68% showed diagnostic features, 20% showed grade-II features and 12% grade-III features. Histo-pathological grading also varied with the duration of the disease. Early lesions showed only grade-II and III picture whereas the diagnostic picture was evident with the longer duration of the disease. In the plaque type, 14 cases showed characteristic histology after three to four months. In conclusion PMLE is commonly observed in females between 21 - 30 years of age. Pruritus is the chief complaint and the time required for the development of rash increases with time of sun exposure. Most common morphological type is papule on the forearm. Papules and plaque type of lesions of PMLE of longer duration clinched the histo-pathological diagnosis.