### Date : 2024-06-23 20:46 ### Topic : Herpes Zoster (Shingles) #medicine #infectology #viralinfection #internalmedicine ---- ### Herpes Zoster (Shingles) Overview **Herpes zoster**, commonly known as **shingles** (대상포진 in Korean), is a viral infection caused by the reactivation of the varicella-zoster virus (VZV), the same virus that causes chickenpox (varicella). After a person recovers from chickenpox, the virus remains dormant in the nerve tissues and can reactivate years later as shingles. ### Etiology - **Causative Agent:** Varicella-zoster virus (VZV). - **Reactivation:** The virus reactivates from its dormant state in the **dorsal root ganglia or cranial nerve ganglia**, typically when the immune system is weakened. ### Risk Factors - **Age:** Most common in individuals over 50 years old. - **Immunocompromised State:** Conditions such as HIV/AIDS, cancer, or use of immunosuppressive medications. - **History of Chickenpox:** Individuals who have had chickenpox are at risk for shingles. ### Pathophysiology 1. **Dormancy:** After initial infection (chickenpox), VZV remains latent in the sensory nerve ganglia. 2. **Reactivation:** Reactivated VZV travels along the nerve fibers to the skin, causing inflammation and a characteristic painful rash. ### Clinical Features **Prodromal Phase:** - Occurs days to weeks before the rash appears. - Symptoms include pain, burning, tingling, or itching in a specific dermatome (area of skin supplied by a single spinal nerve). **Rash Phase:** - **Appearance:** Painful, red rash that develops into clusters of fluid-filled blisters. - **Distribution:** Typically unilateral and follows a single dermatome (most commonly the thoracic or lumbar regions, but can occur anywhere). - **Evolution:** Blisters may break open and crust over within 7-10 days, resolving in 2-4 weeks. - **Pain:** Can be severe and often precedes the rash. -  <Photo from: https://www.health.harvard.edu/diseases-and-conditions/answers-to-common-questions-about-shingles> **Postherpetic Neuralgia (PHN):** - Persistent nerve pain in the affected dermatome lasting for months or even years after the rash has healed. ### Diagnosis **Clinical Diagnosis:** - Based on the characteristic appearance of the rash and its distribution along a dermatome. - History of prior chickenpox infection or exposure. **Laboratory Tests:** - **PCR:** Detects VZV DNA from skin lesions. - **Direct Fluorescent Antibody (DFA) Test:** Identifies VZV in skin lesion samples. - **Serology:** Detects VZV-specific antibodies, though not typically required for diagnosis. ### Example Case Study **Patient Profile:** - **Name:** Jee Hoon Ju - **Age:** 65 - **Occupation:** Retired **Medical History:** - Complaints of severe, burning pain on the right side of the chest for several days, followed by the appearance of a rash. **Clinical Evaluation:** - **Rash Examination:** Unilateral, clustered vesicles on an erythematous base in the right thoracic dermatome. - **Symptoms:** Painful rash, tenderness, and burning sensation. **Laboratory Tests:** - **PCR Test:** Positive for VZV DNA from vesicle fluid. **Diagnosis:** Based on clinical presentation and laboratory confirmation, Jee Hoon Ju is diagnosed with herpes zoster (shingles). ### Management 1. **Antiviral Therapy:** - **Acyclovir, Valacyclovir, or Famciclovir:** Antiviral medications to reduce the severity and duration of the infection, ideally started within 72 hours of rash onset. 2. **Pain Management:** - **Analgesics:** Acetaminophen, NSAIDs for mild pain. - **Opioids:** For severe pain. - **Anticonvulsants:** Gabapentin or pregabalin for nerve pain. - **Antidepressants:** Tricyclic antidepressants for neuropathic pain. 3. **Symptomatic Treatment:** - **Calamine Lotion:** To soothe itching and discomfort. - **Cool Compresses:** To relieve pain and reduce inflammation. 4. **Management of Complications:** - **Postherpetic Neuralgia (PHN):** Long-term pain management strategies, including medications and nerve blocks. ### Prevention 1. **Vaccination:** - **Shingles Vaccine (Shingrix):** Recommended for adults aged 50 and older, and for younger adults at increased risk. - **Zostavax:** An older vaccine, less commonly used now due to the higher efficacy of Shingrix. 2. **Preventive Measures:** - **Avoiding Contact:** People with active shingles should avoid contact with individuals who have never had chickenpox or the chickenpox vaccine, especially pregnant women, newborns, and immunocompromised individuals. ### Prognosis - **Recovery:** Most individuals recover fully within 2-4 weeks. - **Complications:** Postherpetic neuralgia is the most common complication, causing prolonged pain. Other complications can include bacterial skin infections, vision loss (if the eye is affected), and neurological problems. ### Conclusion Herpes zoster (shingles) is a reactivation of the varicella-zoster virus, characterized by a painful, unilateral rash following a dermatome. Early antiviral treatment and effective pain management are crucial in reducing the severity and duration of symptoms. Vaccination is the best preventive measure to reduce the risk of developing shingles and its complications. Understanding the clinical features and management options helps in providing comprehensive care for affected individuals.