This document outlines the process for diagnosing skin diseases. It discusses taking a thorough history including presenting complaints, symptoms, duration, site of involvement, and evolution of lesions. The examination evaluates skin lesions based on morphology, distribution, and configuration. Important investigations are also described such as potassium hydroxide mount to check for fungal infections, Tzanck smear to examine skin blisters cytologically, and various serological tests. A thorough history, physical exam, and selection of appropriate diagnostic tests are essential for accurately diagnosing skin conditions.