Ultrasound Guided Serratus Anterior Versus Erector Spinae Block in Pain Alleviation in Acute Herpes Zoster

Inclusion Criteria: * Adult population between 30 and 75 years old. * Unilateral painful thoracic herpetic eruption of less than one week duration. * VAS more than or equal 4, persistent pain in spite of proper antiviral and analgesic therapy, (800 mg oral acyclovir, 5 times per day, for one week), pregabalin 300 mg per day, acetaminophen 1000 mg per day, topical calamine lotion). Exclusion Criteria: * Diabetic patients. * Painful herpetic eruptive vesicles more than one week. * Abdominal herpetic eruptions. * Non-compliant on anti-viral (bulbar palsy for example). * Co-malignancy or radiotherapy. * Steroid therapy \> 5 mg prednisolone or its equivalent. * Infections or hematoma at site of injection. * Coagulopathy (chronic kidney or liver disease, clopidogrel use).