What is the treatment for chronic itching?

Treatment of Chronic Itching

Start with emollients and topical corticosteroids (hydrocortisone 2.5% or triamcinolone 0.1%) for all patients with chronic pruritus, then escalate based on the underlying cause identified through targeted diagnostic workup. 1, 2

Initial Management for All Patients

• Apply emollients liberally and frequently to maintain skin barrier function and reduce transepidermal water loss 1, 3
• Use topical corticosteroids (medium-to-high potency like triamcinolone 0.1% or clobetasone butyrate) as first-line anti-inflammatory therapy 1, 2
• Add non-sedating antihistamines (fexofenadine 180 mg or loratadine 10 mg daily) for symptomatic relief, though evidence for efficacy in non-urticarial pruritus is limited 1, 3
• Avoid long-term sedating antihistamines except in palliative care settings due to increased dementia risk 1, 3

Cause-Specific Treatment Algorithm

Hepatic Pruritus (Cholestatic Disease)

First-line: Rifampicin (strength of recommendation A) 1, 3

• Second-line: Cholestyramine as bile acid sequestrant 1, 3
• Third-line: Sertraline (SSRI) before opioid antagonists 1, 3
• Fourth-line: Naltrexone or nalmefene (opioid receptor antagonists) 1, 3
• Do NOT use gabapentin in hepatic pruritus (strength of recommendation D) 1, 3
• Consider BB-UVB phototherapy or combined UVA/UVB as adjunctive treatment 1, 3

Uremic Pruritus (Chronic Kidney Disease)

First-line: Optimize dialysis parameters and correct calcium-phosphate imbalances 1, 3

• BB-UVB phototherapy is highly effective (strength of recommendation A) 1, 3
• Consider gabapentin or pregabalin for neuropathic component 1
• Avoid cetirizine specifically in uremic pruritus (ineffective) 1, 3
• Renal transplantation is the only definitive cure 1, 3

Chronic Spontaneous Urticaria

First-line: Non-sedating H1-antihistamines at standard or updosed (up to 4x standard dose) 1

• Second-line: Omalizumab 300 mg subcutaneously every 4 weeks, with updosing to 600 mg every 14 days if insufficient response after 6 months 1
• Third-line: Cyclosporine for omalizumab non-responders, with monitoring of blood pressure and renal function every 6 weeks 1

Pruritus of Unknown Origin (GPUO)

When no underlying cause is identified after comprehensive workup:

• Topical doxepin (limited to 8 days, <10% body surface area, maximum 12g daily) 1, 3
• Topical menthol or pramoxine for cooling/numbing effect 1, 2
• Consider SSRIs (paroxetine or fluvoxamine) or mirtazapine as third-line systemic therapy 1, 3
• Gabapentin or pregabalin for suspected neuropathic component 1, 2

Drug-Induced Pruritus

First step: Discontinue offending medication if risk-benefit analysis permits 1, 3

• For opioid-induced pruritus: Naltrexone (strength of recommendation B) or methylnaltrexone as alternative 1, 3
• For postoperative pruritus: Diclofenac 100 mg rectally 1
• For chloroquine-induced pruritus: Prednisolone 10 mg with or without niacin 50 mg 1

Neuropathic Pruritus (Localized)

• Topical agents: Menthol, pramoxine, or lidocaine as first-line 2, 4
• Gabapentin or pregabalin for systemic neuropathic treatment 2, 4
• Topical capsaicin may be considered despite initial burning sensation 2, 4
• Refer to neurology for underlying nerve pathology evaluation 1, 3

Advanced/Refractory Treatment Options

When First-Line Therapies Fail (approximately 10% of patients)

• Dupilumab (IL-4/IL-13 inhibitor) for inflammatory pruritus refractory to topical therapy 2
• Methotrexate as systemic immunosuppressant 2
• Phototherapy (NB-UVB or BB-UVB) effective across multiple etiologies including psychogenic pruritus 1, 3
• Aprepitant (NK-1 receptor antagonist) for refractory cases 1, 3

Psychogenic/Functional Itch Disorder

• Psychosocial and behavioral interventions: habit reversal training, cognitive restructuring, relaxation techniques 1, 3
• SSRIs or mirtazapine for underlying anxiety/depression 1, 3
• NB-UVB phototherapy may provide benefit 1, 3
• Referral to psychiatry or psychology for comprehensive management 1, 3

Critical Diagnostic Workup to Guide Treatment

Before initiating cause-specific therapy, obtain:

• Complete blood count with differential to assess for hematologic disorders 1, 3, 5
• Comprehensive metabolic panel including liver function tests, creatinine, and blood urea nitrogen 1, 3, 5
• Thyroid-stimulating hormone to exclude thyroid disease 1, 3, 5
• Iron studies and ferritin for iron deficiency or overload 1, 3
• Total IgE and IgG-anti-TPO if chronic spontaneous urticaria suspected 1
• HIV and hepatitis serology if risk factors present 1, 3

Common Pitfalls to Avoid

• Do not use crotamiton cream for GPUO (strength of recommendation B - ineffective) 1
• Do not use topical capsaicin or calamine lotion for GPUO (strength of recommendation D) 1
• Avoid gabapentin specifically in hepatic pruritus despite its utility in other neuropathic conditions 1, 3
• Do not continue sedating antihistamines long-term outside palliative care due to dementia risk 1, 3
• Limit topical doxepin to short courses (8 days maximum) and small areas (<10% BSA) to prevent systemic absorption 1, 3

Special Population Considerations

Elderly Patients

• Exclude asteatotic eczema first with 2-week trial of emollients and topical steroids before extensive workup 3
• Particularly avoid sedating antihistamines due to fall risk and cognitive impairment 1, 3

Cancer-Related Pruritus

• For solid tumors: Paroxetine, mirtazapine, granisetron, or aprepitant 3
• For lymphoma: Cimetidine, carbamazepine, gabapentin, or mirtazapine with BB-UVB for Hodgkin lymphoma 3
• For immune checkpoint inhibitor-induced pruritus: topical corticosteroids, oral antihistamines, and gabapentin/pregabalin for severe cases 1