Infections of the bone and soft tissue of the limbs need to be diagnosed and treated urgently regardless of the patient’s age. Clinical features are often non-specific. MRI and, in some cases, sonography investigations lead to early diagnosis and appropriate management. Computed tomography has limited value. Needle aspiration and biopsy need not be routine. In children, anatomical particularities explain the different morphological manifestations, which vary with age. It is important to both know when to propose the diagnosis of infection, so that appropriate imaging investigations are carried out, and to be aware of the symptomatology of limb infections in children and adults and understand the differential diagnoses for each age group. Clinicians should also be aware of the specific characteristics in children.