Can polycythemia vera cause itching?

Can Polycythemia Vera Cause Itching?

Yes, polycythemia vera definitively causes itching (pruritus), which is a characteristic and common symptom occurring in approximately 48% of patients either at diagnosis or during the disease course. 1

Clinical Characteristics of PV-Associated Pruritus

Aquagenic pruritus is the hallmark presentation—intense itching triggered specifically by contact with water at any temperature, without visible skin lesions. 1 This water-induced itching is so characteristic of PV that it should prompt hematological investigation. 1

Key features include:

• Location: Primarily affects the trunk and proximal extremities 2
• Quality: Most patients (71.8%) describe itching, while others report tickling, stinging, or burning sensations 2
• Severity: Approximately 14.6% of patients classify the pruritus as "unbearable" 2
• Timing: In 64.8% of cases, aquagenic pruritus occurs an average of 2.9 years before the diagnosis of PV is made 2
• Impact: Significantly reduces quality of life, causing sleep deprivation and interference with social and physical activities 1

Pathophysiology

The exact mechanism remains incompletely understood, but platelets and their contents (including prostaglandins and serotonin) are implicated in the pathogenesis. 1 Iron deficiency may also play a contributory role, as there is a significant correlation between active pruritus and low mean corpuscular volume. 1

Diagnostic Approach

When evaluating a patient with generalized pruritus:

• Check complete blood count looking for elevated hemoglobin/hematocrit, microcytosis (suggesting iron deficiency from phlebotomy), elevated white cells or platelets, and low ESR 1
• Test for JAK2 V617F mutation if PV is suspected—this mutation is present in up to 97% of PV cases 1
• Consider PV specifically when aquagenic pruritus is present, even if blood counts appear normal initially 1

Treatment Algorithm

First-Line Management

Low-dose aspirin (81-300 mg daily) should be the initial treatment, as it produces prompt relief (within hours) in most patients by inhibiting platelet release of pruritogenic substances. 1

Second-Line Options

If aspirin fails or provides inadequate relief:

• Selective serotonin reuptake inhibitors (SSRIs) such as paroxetine show response rates higher than 80% 1, 3
• Antihistamines can be tried, though responses are unpredictable and variable 1

Refractory Cases

For intractable pruritus, interferon-α is the recommended treatment, reducing pruritus in up to 81% of affected patients. 1, 3 This has the added benefit of providing cytoreductive therapy for the underlying PV. 1, 4

Alternative therapies with limited evidence include:

• Phototherapy (PUVA or UVB) 1, 5
• Sodium bicarbonate baths (though not consistently effective) 1
• Ruxolitinib (JAK1/JAK2 inhibitor) has shown very effective rapid reductions in pruritus scores in recent trials 1

Critical Clinical Pitfalls

The pruritus can persist despite normalization of blood counts with phlebotomy or cytoreductive therapy, so don't assume hematologic control will resolve the itching. 1 Only 5.6% of patients have complete resolution with PV-directed therapy alone. 2

Avoid indiscriminate iron replacement—while iron deficiency may contribute to pruritus, iron supplementation is not consistently effective and is discouraged without clear indication. 1

Don't dismiss aquagenic pruritus as trivial—it frequently precedes the diagnosis of PV by years and represents a significant quality-of-life issue that warrants aggressive management. 2