Shingles, also known as herpes zoster, occurs after a primary infection of varicella zoster (chicken pox). Ninety-nine percent of Americans age 40 and older have had chicken pox. Approximately 1 million people get shingles each year in the United States. Shingles rates have been increasing for unknown reasons (Centers for Disease Control and Prevention, 2020). One in three persons will develop shingles and the incidence increases with age. Incidence under age 20 is very low but among those older than age 80, 50% will have an episode. Common risk factors include immunosuppression, family history, physical trauma, and age >50 years (Marra et al., 2020). Direct medical and productivity losses for shingles and associated complications are estimated at 2.4 billion annually (Harvey et al., 2020).
Following the original chicken pox infection, the varicella-zoster virus lies dormant in the dorsal root sensory ganglia, cranial and spinal nerves. Shingles occur when the virus is reactivated and spreads from the nerve to the skin in the corresponding dermatome. Most cases are self-limited except in older adults. In phase 1, symptoms include an acute blistering rash, burning, stinging, itching, stabbing pain that may be constant or intermittent. In addition, fever, chills, headache, and upset stomach may be present. Blisters occur in a band-like rash on the trunk (usually thoracic or lumbar areas) or may occur on the face (trigeminal). Rash/pain is always unilateral and never crosses the midline. Herpes zoster occurring in or around the eyes is referred to as herpes zoster ophthamicus and requires immediate referral to an ophthalmologist to avoid serious eye problems including corneal ulcers, inflammation, glaucoma, and loss of vision.
Inflammation of the sensory nerves and skin may last up to 30 days. Blisters scab in 7 to 10 days and fully clear up in 2 to 4 weeks. Patients should be advised to avoid small children and pregnant women until the rash is completely resolved. In phase 2, pain persists but resolves within 3 months of onset. Pain that persists beyond 90 days after onset of rash indicates postherpetic neuralgia (PHN).
For best outcomes, treatment should be initiated within 72 hours and prior to crusting of lesions. Treatment with antiviral medications (Table 1), helps with healing of the rash, decreases viral shedding, and may or may not prevent PHN. In a meta-analysis, valacyclovir and famciclovir were the most effective antivirals with less dosing schedules than acyclovir (Pott Junior et al., 2018). Pain management (Table 2) is based on mild or moderate-to-severe pain that interferes with sleep, appetite, or libido. In phase 1, aspirin and nonsteroidal anti-inflammatories are of limited value, except with mild pain.
Risk factors of PHN, which occurs in 10% to 15% of cases, are advanced age, immune status, and clinical course with severe pain and rash during phase 1 (Forbes et al., 2016). Debilitating pain is in the same distribution as the previous rash and may last for years postinfection. First-line treatment with gabapentin and pregabalin has moderate quality evidence for moderate-to-severe pain but needs to be used carefully with renal insufficiency. Amitriptyline has some efficacy and may be used if first-line drugs are not tolerated; however, it may cause confusion in older adults. In addition, topical capsaicin and lidocaine for mild-to-moderate localized pain may be helpful. It is recommended to avoid opioids as much as possible (Edelsberg et al., 2011). Pain intensity directly impacts quality of life and activities of daily living.
The effectiveness of acupuncture has been debated-a meta-analysis supports reduced pain intensity, and relief of anxiety which in turn improves quality of life; however, the sample size in studies is small (Pei et al., 2019).
Recent large population studies have indicated that adults with shingles especially occurring on the face have an increased risk for stroke and myocardial infarction (MI), especially in the 3 to 12 months postrash, due to inflammation of the vascular system, particularly arteries (Breuer et al., 2014). A subsequent comprehensive review suggested up to a fourfold higher risk for stroke or MI within 1 year after an episode in those over age 40 (Wu et al., 2019).
Shingles is a preventable disease. In 2017, the Shingrix vaccination became available for those age 50 and older. It consists of 2 intramuscular doses, 2 to 6 months apart and has been 97% effective for those age 50 to 69, and 91% effective for those age 70 or above. Side effects may include fatigue, muscle pain, headache, fever, nausea, and stomach pain for a short duration (Hesse et al., 2019). Encourage patients to discuss this with their primary care provider.
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