What are the key differential diagnoses to consider in a patient presenting with generalized pruritus?

When a patient presents with generalized pruritus, key differential diagnoses to consider include systemic diseases such as cholestatic liver disorders, chronic kidney disease, haematological malignancies (notably lymphoma), thyroid dysfunction, and diabetes mellitus. Additionally, dermatological conditions, drug reactions, and psychological causes should be evaluated. It is essential to exclude malignancy, particularly lymphoma, as pruritus can be an early systemic symptom. Other systemic causes include iron deficiency anaemia and polycythaemia vera. A thorough history, examination, and targeted investigations are critical to identify underlying causes and guide management ¹ (Greaves, 2005).

Specifically, cholestatic liver diseases (e.g., primary biliary cholangitis) often cause pruritus due to bile salt accumulation. Chronic kidney disease can lead to uraemic pruritus. Haematological disorders, especially Hodgkin lymphoma, are well-recognised causes of generalized itch. Endocrine disorders such as hyperthyroidism or hypothyroidism may also present with pruritus. Drug-induced pruritus should be considered, particularly with medications known to cause this side effect. Psychological factors, including anxiety and depression, may exacerbate or mimic pruritus ¹ (Greaves, 2005).

In summary, the differential diagnosis of generalized pruritus is broad and includes systemic, dermatological, drug-related, and psychological causes. Prompt recognition of serious underlying conditions, especially malignancy, is vital for timely referral and management ¹ (Greaves, 2005).