Can itching be caused by something other than gabapentin (Neurontin)?

Yes, Itching Can Absolutely Be Caused by Many Conditions Other Than Gabapentin

Itching (pruritus) has numerous potential causes beyond medication side effects, including systemic diseases, skin conditions, malignancies, and metabolic disorders that must be systematically evaluated. 1

Major Categories of Pruritus Beyond Medications

Systemic Disease-Related Causes

Chronic Kidney Disease (Uremic Pruritus)

• Occurs in 60-90% of patients with CKD stages 4-5 and those on dialysis 2, 3
• Associated with disrupted sleep, reduced quality of life, depression, and increased mortality 2
• Typically presents as severe, generalized itching (median severity 8/10) that doesn't respond to antihistamines 2
• Check serum calcium (should be ≤2.60 mmol/L), phosphate (≤1.8 mmol/L), and ensure adequate dialysis 1, 2

Liver Disease (Hepatic Pruritus)

• Cholestatic conditions are a common cause of generalized pruritus 1, 4
• Evaluate liver function tests, bile acids, and consider imaging for biliary obstruction 1
• Characterized by intense itching that worsens at night 1

Hematological Malignancies

• Lymphoma (both Hodgkin and non-Hodgkin) frequently causes pruritus 1
• Polycythemia vera causes aquagenic pruritus (triggered by water contact) in 60-70% of patients 1
• Look for lymphadenopathy, fever, weight loss, and unexplained blood count abnormalities 1
• Iron deficiency or iron overload can both cause generalized itching 1

Solid Malignancies

• Breast, colorectal, and other solid tumors can cause paraneoplastic pruritus 1
• Evaluate for constitutional symptoms, weight loss, and organ-specific symptoms 1

Drug-Induced Pruritus (Other Than Gabapentin)

Opioid-Induced Pruritus

• Occurs in 60-70% of patients receiving epidural morphine 1
• Generalized itching without skin lesions is characteristic 1
• Epidural dexamethasone has also been associated with generalized pruritus 1

Chloroquine-Induced Pruritus

• Affects 60-70% of patients of African background during malaria treatment 1
• Severe and generalized without skin lesions 1
• Uncommon in other ethnic groups 1

Cancer Biological Therapies

• Epidermal growth factor inhibitors commonly cause pruritus 1
• Interleukin-2 therapy frequently causes pruritus with associated eosinophilia 5

Neuropathic Causes

Brachioradial Pruritus

• Deep intense itching, tingling, or burning localized to dorsolateral upper extremities 6
• Caused by cervical radiculopathy combined with sun exposure 6
• Occurs primarily in late summer in fair-skinned individuals with extensive sun exposure 6
• Does not respond to topical steroids or antihistamines 6

Notalgia Paresthetica

• Localized neuropathic itch, typically on the back 4, 7
• Related to nerve compression or damage 7

Systematic Evaluation Approach

Initial Assessment

• Medication review: Trial cessation of any potentially causative medications if risk-benefit analysis is acceptable 1
• Laboratory screening: Complete blood count, comprehensive metabolic panel, liver function tests, thyroid function, iron studies 1
• Renal function: Creatinine, eGFR, calcium, phosphate, parathyroid hormone if CKD suspected 1, 2
• Malignancy screening: Chest X-ray, abdominal ultrasound if constitutional symptoms present 1
• Infectious causes: Consider screening for malaria, strongyloidiasis, schistosomiasis, hepatitis B and C serology based on exposure history 1

Physical Examination Focus

• Examine for xerosis (dry skin), which is extremely common and often overlooked 4
• Look for lymphadenopathy, hepatosplenomegaly, jaundice 1
• Check for signs of chronic liver disease or uremia 1
• Assess for primary dermatological conditions that may have been missed 1

Critical Pitfalls to Avoid

Don't assume antihistamines will work for non-histamine-mediated itch

• 63% of uremic pruritus patients had already failed antihistamines before effective treatment 2
• Cetirizine is specifically not effective in uremic pruritus 1
• Long-term sedative antihistamines should be avoided except in palliative care due to dementia risk 1, 4

Don't overlook xerosis as a contributing factor

• Dry skin is an extremely common and treatable contributor to pruritus 4
• Regular emollient use should be first-line regardless of underlying cause 1, 4

Don't use gabapentin for hepatic pruritus

• Gabapentin should be specifically avoided in liver disease-related pruritus 1, 4
• This is a critical contraindication despite its efficacy in other pruritus types 1

Don't miss the temporal relationship with water exposure

• Aquagenic pruritus is highly specific for polycythemia vera 1
• Ask specifically about itching triggered by bathing or showering 1