What are the treatment options for chronic pruritis?

Treatment Options for Chronic Pruritus

The treatment of chronic pruritus should be targeted to the underlying cause, with first-line therapy including topical corticosteroids for inflammatory causes and neuromodulators for neuropathic causes. 1

Diagnostic Approach

Before initiating treatment, identify the underlying cause:

• Check for systemic diseases: liver disease, kidney disease, hematologic malignancy, thyroid disease
• Consider drug-induced causes and discontinue medications if possible
• Evaluate for dermatological conditions
• Assess for neuropathic causes

Treatment Algorithm Based on Etiology

1. Generalized Pruritus of Unknown Origin (GPUO)

First-line treatments:

• Self-care advice and emollients 1
• Topical therapies:
  • Topical doxepin (limit to 8 days, 10% body surface area, 12g daily) 1
  • Topical clobetasone butyrate or menthol 1
  • Avoid: crotamiton cream, topical capsaicin, calamine lotion (ineffective) 1

Second-line treatments:

• Non-sedating antihistamines: fexofenadine 180mg or loratadine 10mg 1
• Mildly sedating antihistamines: cetirizine 10mg 1
• Consider H1 and H2 antagonist combinations (e.g., fexofenadine and cimetidine) 1

Third-line treatments:

• Neuromodulators: gabapentin, pregabalin 1, 2
• Antidepressants: paroxetine, fluvoxamine, mirtazapine 1
• Opioid antagonists: naltrexone, butorphanol 1
• Other agents: ondansetron, aprepitant 1

2. Specific Causes of Pruritus

Hepatic Pruritus

1. Rifampicin (first-line) 1
2. Cholestyramine (second-line) 1
3. Sertraline (third-line) 1
4. Naltrexone or nalmefene (fourth-line) 1
5. Do not use gabapentin in hepatic pruritus 1

Uremic Pruritus

1. Optimize dialysis, normalize calcium-phosphate balance, control PTH levels 1
2. BB-UVB phototherapy (strongest evidence, recommendation A) 1
3. Consider capsaicin cream, topical calcipotriol, or oral gabapentin 1
4. Avoid: Cetirizine (ineffective), long-term sedative antihistamines 1

Drug-Induced Pruritus

1. Trial of medication cessation if benefit-risk analysis permits 1
2. For opioid-induced pruritus: naltrexone or methylnaltrexone 1
3. For chloroquine-induced pruritus: prednisolone 10mg, niacin 50mg, or combination 1

Lymphoma-Associated Pruritus

• Cimetidine, carbamazepine, gabapentin, or mirtazapine 1
• For incurable lymphoma: oral corticosteroids 1
• Phototherapy: BB-UVB (Hodgkin) or NB-UVB (non-Hodgkin) 1

Polycythemia Vera

• Cytoreductive therapy, aspirin, interferon-α, SSRIs 1
• Phototherapy options: NB-UVB, BB-UVB, PUVA 1

Neuropathic Pruritus (including Brachioradial Pruritus)

• Topical treatments: medium to high-potency corticosteroids, menthol, topical doxepin 3
• Systemic treatments: gabapentin or pregabalin 3, 2
• Referral to relevant specialist 1

Special Considerations

Topical Corticosteroids

• For inflammatory causes, use hydrocortisone 2.5% or triamcinolone 0.1% 2
• For potent options like clobetasol propionate, limit treatment to 2 weeks with total dosage not exceeding 50 mL/week 4

Psychological Factors

• Consider psychosocial and behavioral interventions 1
• Patient support groups can be beneficial 1
• Consider referral to social workers, liaison psychiatry, or psychologists 1

Phototherapy Options

• BB-UVB is effective for many forms of pruritus, particularly uremic pruritus 1
• NB-UVB can be beneficial for psychogenic pruritus and lymphoma-associated pruritus 1

Common Pitfalls to Avoid

• Using sedative antihistamines long-term (may predispose to dementia) 1
• Using ineffective treatments like crotamiton cream 1
• Failing to identify and treat underlying systemic disease 2
• Using gabapentin in hepatic pruritus 1
• Inadequate treatment duration or monotherapy approach when combination therapy may be more effective 3

Chronic pruritus significantly impacts quality of life and requires a systematic approach to diagnosis and treatment. The treatment strategy should be tailored to the underlying cause, with consideration of both topical and systemic options based on the severity and etiology of the pruritus.