Which symptom is classically associated with PV due to increased RBC mass?

• A. Pruritus after hot baths
• B. Chest pain only with exertion
• C. Severe edema of legs
• D. Jaundice

Answer: (A)

Aquagenic pruritus is a classic feature of polycythemia vera, reflecting the consequences of increased red cell mass. The enlarged red cell volume thickens the blood (hyperviscosity) and goes hand in hand with clonal proliferation driven by mutations like JAK2. The itchy sensation after contact with water, especially hot water, comes from mediator release—histamine—from expanded basophils and cutaneous mast cells in PV. This pruritus is a distinctive clue that points toward PV, whereas chest pain with exertion, leg edema, or jaundice are not the typical, defining symptoms linked specifically to the increased RBC mass in this condition.