Spectrum of non-infectious erythematous, papular and squamous lesions of the skin

Background : Dermatopathologists base their diagnostic approach on the tissue reaction pattern. This study mainly includes the interpretation of two major tissue reaction patterns, the psoriasiform and the lichenoid reactions, with clinicopathological correlation. Aims : To analyze the spectrum of non-infectious erythematous papular and squamous lesions of the skin at our institute, study the age, sex and anatomic distribution pattern and classify the lesions into major categories; determine the incidence of each subcategory. Materials and Methods : Study period: two years; prospective, sample size: 161 cases, proforma filled. Results : The lesions comprised 15.80% of the total load of surgical pathology and 30.99% of total number of skin biopsies. The highest percentage was in the 30-40 year age group (28.6%) with a male preponderance of 60.25%. The extremities were most frequently involved (67.79%). Lichenoid lesions were the commonest (46.57%) with lichen planus 26.7% and psoriasis vulgaris-19.88% being the most frequent. There were 5.6% seropositive cases. Correlation with the histopathological diagnosis was positive in 97.52% cases and negative in 2.48% cases. Conclusion: The contribution of histopathology to the final diagnosis was significant. It confirmed the diagnosis in 92.55% and gave the diagnosis in 4.97% cases.