[Pruritus in systemic diseases : Common and rare etiologies]

Area of Science:

• Internal Medicine
• Dermatology
• Pharmacology

Background:

• Chronic pruritus is a symptom of internal disorders, distinct from primary skin diseases.
• Intense scratching can lead to secondary skin changes like excoriation and scarring.
• Common internal causes include chronic kidney disease, hepatobiliary disorders, hematological disorders, and adverse drug reactions.

Purpose of the Study:

• To review the internal causes of chronic pruritus.
• To discuss the pathogenesis and treatment challenges of internal pruritus.
• To summarize current therapeutic strategies for pruritus associated with specific internal disorders.

Main Methods:

• Literature review of internal causes of chronic pruritus.
• Summary of pathogenetic insights for uremic and cholestatic pruritus.
• Overview of established and emerging antipruritic treatments.

Main Results:

• Gabapentin and pregabalin are effective for chronic kidney disease-associated pruritus.
• Nalfurafine (a κ-opioid receptor agonist) is licensed in Japan for uremic pruritus.
• Cholestyramine, rifampicin, bezafibrate, and μ-opioid receptor antagonists show efficacy in cholestatic pruritus.

Conclusions:

• Antipruritic treatment for internal disorders is often symptomatic and challenging.
• Targeting the underlying disease is crucial for effective pruritus management.
• Further research, including randomized controlled trials, is needed for pruritus in other internal disorders.