What is Plethora (Ruddy) in Polycythemia Vera
Plethora in polycythemia vera refers to the characteristic ruddy, reddish-purple facial complexion and skin appearance that results from the markedly increased red blood cell mass and engorged superficial blood vessels. 1
Clinical Manifestation
Plethora represents one of the classic clinical phenotypes of PV that was recognized even before the disease was formally described by Vaquez in 1903. 1 The physical finding consists of:
- A ruddy or reddish-purple discoloration of the face and skin, particularly noticeable in sun-exposed areas 1
- Engorged superficial veins that are visibly distended due to increased blood volume 1
- Conjunctival injection with redness of the eyes 1
Pathophysiologic Basis
The plethoric appearance directly results from:
- Elevated red blood cell mass causing increased blood viscosity and volume 2
- Increased hemoglobin concentration (>16.5 g/dL in men or >16.0 g/dL in women) that gives blood its deeper red color 2
- Vascular engorgement from the expanded blood volume filling superficial vessels 1
Clinical Significance
Plethora serves as an important diagnostic clue when evaluating patients for PV, though it is not universally present. 1 The finding should prompt:
- Measurement of hemoglobin and hematocrit levels to confirm erythrocytosis 2
- JAK2 mutation testing, as >95% of PV patients harbor this mutation 2, 3
- Evaluation for splenomegaly (present in 36% of patients) and other PV manifestations 2
The plethoric appearance typically improves with therapeutic phlebotomy as hematocrit is reduced to target levels below 45%, which is the cornerstone of PV management. 1, 2, 4