What is the initial workup and treatment for a patient presenting with pruritus?

Initial Workup and Treatment for Pruritus

The initial workup for generalized pruritus should include a thorough history, physical examination, and basic laboratory tests including full blood count, ferritin levels, liver function tests, and urea and electrolytes to identify underlying causes. 1

Initial Assessment

History and Examination

• Assess for:
  • Duration and pattern of pruritus
  • Presence or absence of rash
  • Systemic symptoms (weight loss, fever, night sweats)
  • Medication history
  • Travel history
  • Aquagenic pruritus (triggered by water contact)
  • Timing (nocturnal pruritus may suggest lymphoma)

Basic Laboratory Investigations

• First-line tests for generalized pruritus without rash (GPWOR):
  • Full blood count and ferritin levels 1
  • Liver function tests 1
  • Urea and electrolytes 1
  • Blood film, lactate dehydrogenase, and ESR if hematological cause suspected 1

Additional Targeted Investigations

• Do not routinely perform full investigations to rule out malignancy 1
• Do not routinely perform endocrine investigations (including thyroid function tests) unless clinical features suggest endocrinopathy 1
• Consider HIV and hepatitis serology if risk factors present 1
• Consider JAK2 V617F mutation analysis if polycythemia vera suspected (elevated hemoglobin/hematocrit) 1

Treatment Approach

First-Line Treatment

• Emollients applied liberally and frequently (at least twice daily) 1, 2
• Self-care measures:
  • Keep fingernails short
  • Avoid trigger factors
  • Use mild soaps
  • Apply cool compresses for immediate relief 2

Pharmacological Treatment

• Non-sedating antihistamines (e.g., fexofenadine 180 mg or loratadine 10 mg) 2
• Medium to high-potency topical corticosteroids for localized areas 2, 3
  • Apply to affected areas 2-3 times daily 3
  • Consider occlusive dressing technique for recalcitrant conditions 3

Second-Line Treatment

• Consider combination of H1 and H2 antagonists (e.g., fexofenadine and cimetidine) 2
• Gabapentin or pregabalin for neuropathic component 2
• Antidepressants with antipruritic effects (paroxetine or mirtazapine) 2
• Phototherapy (NB-UVB or BB-UVB) 1, 2

Special Considerations

Elderly Patients

• Avoid sedating antihistamines due to increased risk of side effects and potential dementia risk 2
• Use high lipid content moisturizers 2
• Consider vitamin D supplementation 1

Treatment Based on Underlying Cause

• Iron deficiency: Iron replacement 1
• Iron overload: Venesection or desferrioxamine infusion 1
• Polycythemia vera: Consider cytoreductive therapy, aspirin, interferon-α, SSRIs, or phototherapy 1
• Lymphoma: Consider cimetidine, carbamazepine, gabapentin, or mirtazapine 1
• Uremic pruritus: Ensure adequate dialysis, normalize calcium-phosphate balance, correct anemia 1

When to Refer

• Diagnostic uncertainty
• Failure of primary care management to relieve symptoms
• Suspicion of significant hepatic impairment
• Suspicion of hematological disorders (polycythemia vera or lymphoma)
• Suspicion of neuropathic pruritus requiring specialist evaluation 1

Common Pitfalls to Avoid

• Overinvestigating for malignancy without appropriate systemic symptoms
• Performing routine endocrine investigations without clinical indication
• Using sedating antihistamines long-term, especially in elderly patients
• Using calamine lotion or crotamiton cream (limited evidence for effectiveness) 2
• Failing to follow up patients with persistent unexplained pruritus (underlying causes may not be initially evident) 2

Remember that generalized pruritus may have a significant underlying cause in 20-30% of cases, making thorough initial assessment and appropriate follow-up essential 1, 2.