This document provides guidance on evaluating and diagnosing childhood arthritis. It distinguishes arthritis from arthralgia based on clinical features. It lists various differential diagnoses for childhood joint pain or swelling including infectious, rheumatological, neoplastic and traumatic etiologies. It describes tender points seen in fibromyalgia. It outlines features that can distinguish inflammatory, mechanical and sinister causes of joint pain. The approach involves assessing onset, number and type of joints involved, associated systemic symptoms and precipitating factors. Key clues from history and physical exam are described. A review of systems guides evaluation of specific organ systems. Common clinical presentations like acute monoarthritis, chronic monoarthritis and polyarthritis are reviewed. Characteristics of juvenile idiopathic arthritis subtypes