In a 78-year-old woman with unremarkable past medical history presenting with months of upper‑body pruritus and an isolated elevated lactate dehydrogenase (LDH 408 U/L), what work‑up and management should be pursued?

Workup and Management for 78-Year-Old Woman with Chronic Pruritus and Elevated LDH

This patient requires urgent hematologic evaluation with specific focus on lymphoma, given the combination of chronic pruritus and significantly elevated LDH (408 U/L, nearly double the upper limit of normal). 1

Immediate Diagnostic Workup

The British Association of Dermatologists guidelines explicitly recommend that patients with generalized pruritus and suspicion of hematological involvement should have:

• Complete blood count with differential and blood film - to assess for polycythemia vera, leukemia, or lymphoma 1
• ESR (if available) - low ESR with elevated hemoglobin suggests polycythemia vera 1
• Peripheral blood smear review - critical for identifying abnormal cells 1

The elevated LDH is particularly concerning in this context. While LDH has limited diagnostic utility as a screening tool in undifferentiated pruritus 2, when already elevated, it serves as a marker for hematologic malignancy - specifically lymphoma, which accounts for approximately 2% of generalized pruritus cases 1. Recent data shows patients with pruritus have a 4.42-fold increased risk of Hodgkin lymphoma and 2.35-fold increased risk of non-Hodgkin lymphoma within the first year 2.

Critical Clinical Assessment

Perform a targeted history and examination focusing on:

• B symptoms: Night sweats, fever, unintentional weight loss (suggestive of lymphoma) 1, 3
• Aquagenic pruritus: Itching triggered by water contact (characteristic of polycythemia vera) 1
• Timing: Nocturnal itching with systemic symptoms strongly suggests lymphoma 1
• Lymphadenopathy: Palpate all nodal chains; any enlarged nodes require excision or ultrasound-guided core biopsy 1
• Hepatosplenomegaly: Examine for organomegaly 1

Important caveat: Absence of palpable lymphadenopathy does NOT exclude lymphoma - a recent case report documented Hodgkin lymphoma presenting with chronic pruritus and elevated LDH without palpable nodes 3.

Secondary Investigations Based on Initial Results

If CBC suggests polycythemia vera (elevated hemoglobin/hematocrit, microcytosis, elevated platelets/WBC, low ESR):

• JAK2 V617F mutation analysis (present in up to 97% of PV cases) 1
• If JAK2 negative: serum erythropoietin, oxygen saturation, chest X-ray, abdominal ultrasound 1

If lymphoma suspected (abnormal blood film, B symptoms, or persistent unexplained pruritus):

• Chest imaging (CT or X-ray) - essential even without palpable lymphadenopathy 3
• Consider skin biopsy from trunk - rarely, cutaneous lymphoma presents with pruritus and normal-appearing skin 1
• Immunoglobulins and urinary paraproteins may be requested but have low yield (myeloma rarely causes pruritus) 1

Hematology referral indications:

Refer to hematology if:

• Abnormal CBC or blood film
• Elevated hemoglobin/hematocrit suggesting PV
• Any suspicion of lymphoma
• Persistent unexplained pruritus with elevated LDH 1

Management Considerations

Symptomatic relief while awaiting workup:

The evidence for symptomatic treatment is limited to case reports, but options include:

For lymphoma-associated pruritus:

• Gabapentin, carbamazepine, or mirtazapine 1
• Phototherapy (UVB or PUVA) 1
• High-dose oral corticosteroids (particularly for palliation) 1

For PV-associated pruritus:

• Aspirin 300 mg daily 1
• SSRIs 1
• UVB phototherapy 1

Common pitfalls to avoid:

1. Do not dismiss elevated LDH as nonspecific - in the context of chronic pruritus, it warrants thorough hematologic investigation 2, 4
2. Do not delay imaging if B symptoms present - chest imaging is critical even without palpable nodes 3
3. Do not assume xerosis in elderly patients - while xerosis is the most common cause of pruritus in the elderly 5, this patient's significantly elevated LDH demands exclusion of malignancy first
4. The highest cancer risk is within the first 12 months of pruritus presentation 2, making urgent evaluation essential

Definitive treatment:

Treatment of the underlying hematologic malignancy (if identified) will resolve the pruritus 1. Curative treatment of lymphoma invariably resolves associated pruritus 1.

The priority is rapid hematologic evaluation given the 4-fold increased lymphoma risk in the first year after pruritus presentation combined with markedly elevated LDH. 2