What is the recommended treatment for urticaria in a patient with impaired renal function undergoing dialysis?

Treatment of Urticaria in Dialysis Patients

For true urticaria (hives) in dialysis patients, omalizumab 150-300 mg subcutaneously every 4 weeks is the evidence-based treatment, as dosing is not dependent on renal function or body weight. 1

Critical Distinction: Urticaria vs. Uremic Pruritus

Before proceeding with treatment, you must differentiate between:

• True urticaria (hives): Raised, erythematous wheals that blanch with pressure, typically lasting <24 hours 2
• Uremic pruritus: Generalized itching without primary skin lesions (except excoriations), common in 22-74% of dialysis patients 3

The treatment approaches are completely different.

Treatment for True Urticaria (Chronic Spontaneous Urticaria)

First-Line Treatment

• Omalizumab 150-300 mg subcutaneously every 4 weeks is FDA-approved for chronic spontaneous urticaria in patients ≥12 years who remain symptomatic despite H1-antihistamine treatment 1
• The 300 mg dose can be given as one 300 mg/2 mL injection or two 150 mg/mL injections 1
• Key advantage: Dosing is completely independent of renal function, serum IgE levels, or body weight 1

Second-Line: Antihistamine Selection (with caution)

If antihistamines are attempted before omalizumab:

• Fexofenadine 180 mg daily is the preferred second-generation antihistamine as it requires no dose adjustment in renal impairment 4
• Avoid cetirizine and levocetirizine in severe renal impairment (CrCl <10 mL/min) 4
• Use loratadine with extreme caution in severe renal impairment 4
• Up to 4-fold conventional doses of antihistamines may be needed for difficult-to-treat urticaria, though this evidence is not specific to dialysis patients 5

Important Pitfalls

• Avoid long-term sedating antihistamines (diphenhydramine, hydroxyzine) except in palliative care, as they may predispose to dementia 6, 7, 4
• Standard antihistamines often have limited efficacy in dialysis patients and require dose adjustments 8
• Always administer once-daily medications after dialysis when possible 8

Treatment for Uremic Pruritus (If Misdiagnosed as Urticaria)

If the patient actually has uremic pruritus rather than true urticaria:

Optimize Dialysis Parameters First

• Ensure adequate dialysis with target Kt/V of approximately 1.6 6, 7
• Normalize calcium-phosphate balance and control parathyroid hormone levels 6, 7
• Correct anemia with erythropoietin if present 7
• Provide emollients for xerosis (dry skin), the most common cutaneous sign in dialysis patients 7

Pharmacologic Treatment

• Gabapentin 100-300 mg after each dialysis session (three times weekly) is the most effective medication for uremic pruritus, with significantly lower doses than non-ESRD populations 6, 7
• Topical capsaicin 0.025% cream applied four times daily can provide marked relief 6, 7
• Broad-band UVB phototherapy is effective for many patients 7

What NOT to Use for Uremic Pruritus

• Cetirizine is ineffective specifically for uremic pruritus despite efficacy in other conditions 6, 7, 4
• Standard antihistamines have limited efficacy for uremic pruritus 7, 4

Monitoring and Safety

• For omalizumab: Initiate therapy in a healthcare setting due to anaphylaxis risk; consider self-administration only after ≥3 doses without hypersensitivity reactions 1
• Periodically reassess the need for continued therapy based on symptom control 1
• Start all medications at low doses and increase gradually in dialysis patients 8