Localized: treat rash, fungal/bacterial infection
Systemic: secondary to organ failure and cancer
Non-histaminergic receptors transmit signals to spinal cord. Similar to pain, itch can undergo central sensitization.
Treatment
- Treat dry skin
- Lidocaine 2-10% ointment/lotion used for localized itch. Toxicity possible if used over large areas
- Camphor 0.5% Menthol 0.5% in ointment base PRN
- Gabapentin 100-300mg daily / pregabalin 25 –50mg daily (adjust dose for renal failure)
- Sertraline 50-100mg daily/ paroxetine 5-10mg daily at bedtime
- Mirtazapine 7.5 – 15mg daily
- Rifampicin 300-600mg daily in cholestatic itch
Refractory itch: consider aprepitant 80mg/day, naltrexone 50mg / montelukast 10mg in uremic itch