A 64-year-old woman presents to the emergency room with whole-body itching. She noticed her symptoms while in the bathtub at home. She has never had symptoms like this before. Over the previous several months she has had episodes of joint swelling and pain in her hands as well as redness, burning pain, and swelling of her hands and feet. Her medical history is significant for type 2 diabetes mellitus, hypertension, and osteoporosis for which she takes metformin, enalapril, and alendronate. She was found to have a deep vein thrombosis of her left leg 3 months prior to presentation. Her temperature is 98.6°F (37.0°C), pulse is 80/min, blood pressure is 135/85 mmHg, and respirations are 13/min. Physical exam is notable for a woman in discomfort with excoriations over the skin on her forearms. Laboratory tests are shown below.

Serum:
Na+: 135 mEq/L
Cl-: 100 mEq/L
K+: 5.0 mEq/L
HCO3-: 22 mEq/L
BUN: 19 mg/dL
Glucose: 130 mg/dL
Creatinine: 1.0 mg/dL

Hematocrit: 64%
Leukocyte count: 19,000 cells/mm^3 with normal differential
Platelet count: 900,000/mm^3

Which of the following is the most appropriate long-term treatment?
Hydroxyurea
Cyclophosphamide
Prednisone
Diphenhydramine
Hydroxyurea
This patient presents with polycythemia, leukocytosis, and thrombocytosis in the setting of pruritus after bathing, as well as episodes suggestive of acute gout flares. These findings are consistent with polycythemia vera, which can be treated with hydroxyurea.

Polycythemia vera is a malignancy of the bone marrow that results in the overproduction of red blood cells, platelets, and white blood cells. Classic symptoms include pruritus after hot baths as well as swelling, burning pain, and rubor of the hands and feet (erythromelalgia). Patients may also have gout due to increased cell turnover leading to hyperuricemia. Older patients (> 60 years old) and those with prior thrombosis should be treated with a myelosuppressive agent, most commonly hydroxyurea with or without aspirin. Therapeutic phlebotomy is often indicated on these patients.

Stuart and Viera review the evidence regarding the diagnosis and treatment of polycythemia vera. They discuss how treatment includes phlebotomy with the possible addition of myelosuppressive agents. They recommend consultation with a hematologist for any patients with this syndrome.

Incorrect Answers:
Answer A: Cyclophosphamide is a chemotherapeutic agent that is used in the treatment of certain leukemias and lymphomas, as well as severe symptoms of autoimmune disease. A malignancy would present with vague systemic symptoms, weight loss, malaise, and abnormalities detected on CBC. Cyclophosphamide is not used in the treatment of polycythemia vera.

Answer B: Diphenhydramine is a 1st-generation antihistamine that can be used to treat pruritus, but would not be indicated for the treatment of polycythemia vera which is the underlying condition. This treatment represents a symptomatic treatment versus an agent that addresses the underlying cause.

Answer C: Febuxostat is a xanthine oxidase inhibitor that is used to reduce uric acid levels in the management of chronic gout. Gout would present with acute severe joint pain (typically the great toe) with risk factors of alcohol use, obesity, and thiazide use. It is not used in the acute management of gout or in polycythemia vera.

Answer E: Prednisone is a glucocorticoid that is used in many different clinical situations but is not used in the management of polycythemia vera. It could be used in acute inflammatory conditions (like Crohn disease or granulomatosis with polyangiitis) or to reduce inflammation during a flare of asthma or COPD.

Bullet Summary:
Polycythemia vera presents with pruritus after bathing, erythromelalgia, and gout and should be treated with hydroxyurea with or without aspirin.