How can I differentiate between a self-limiting fever and one that requires further investigation in adults?

To differentiate between a self-limiting fever and a fever requiring further investigation in adults, consider the following:

• Assess for red flag symptoms and signs of serious illness: Look for immediately life-threatening features such as compromised airway, breathing or circulation, decreased level of consciousness, or signs suggestive of sepsis. Presence of these signs warrants urgent further investigation and management ¹.
• Evaluate the clinical context and associated symptoms: Fever accompanied by symptoms such as a non-blanching rash, neck stiffness, bulging fontanelle (in infants), focal neurological signs, or signs of pneumonia (e.g., tachypnoea, chest indrawing, cyanosis) should prompt further investigation ¹.
• Consider duration and progression: A fever that persists longer than expected for a self-limiting illness or worsens over time should be investigated further ¹.
• Use clinical judgement and risk assessment tools: In children, the NICE traffic light system is used to stratify risk; while this is paediatric-focused, the principle of assessing risk based on symptoms and signs applies to adults as well ¹.
• Consider patient factors: Underlying comorbidities, immunosuppression, recent travel, or exposure to serious infectious diseases increase the likelihood that a fever requires further investigation ¹.
• Provide safety netting advice: If no immediate cause is found but concern remains, advise patients on warning symptoms and when to seek further care ¹.

In summary, a self-limiting fever is typically associated with mild symptoms, no signs of systemic compromise, and resolves within a few days, whereas a fever requiring further investigation is accompanied by red flag signs, systemic symptoms, or risk factors indicating possible serious infection or other pathology ¹.