Understanding the Histomorphological Spectrum of Psoriasiform Dermatitis

Background: Psoriasiform dermatitis is a term that refers to a group of disorders which histologically and/or clinically mimic psoriasis. It often poses diagnostic dilemma to both pathologists and dermatologists. It is essential to follow a systematic approach and use appropriate clinicopathological correlation to arrive at a diagnosis. Histopathological material constitutes definite hard evidence, which can be preserved and will continue to be available for future review. The objective of this study is to understand the histopathological features of psoriasiform disorders and to highlight the characteristic microscopic difference between them for better approach of the diagnosis. Methods: This was a retrospective cross-sectional study conducted at tertiary care hospital in Bangalore. All cases diagnosed as psoriasis or mentioned as one of the differential diagnoses were included in the study. The material included 25 skin biopsies. Results: Most of the cases were noted in the age group of 21-30 years. The sex distribution pattern revealed male predominance with male to female ratio of 1.7:1. Psoriasis was the most common lesion noted followed by Pityriasis rosea and Pityriasis rubra pilaris. Parakeratosis and acanthosis were the most common histological features observed in cases of psoriasis. Dermal infiltrate and acanthosis were the common feature which was seen in almost all biopsy samples. Conclusion: Clinically, psoriasiform lesions appear as classical psoriasis, however microscopically there are different classifications of psoriasiform disorders. Since satisfactory management of these conditions require both symptomatic and specific therapy, it is essential to reach a definitive diagnosis. Histopathology is the gold standard for diagnosis. Clinicopathological correlation is must for correct diagnosis and appropriate treatment.