A patient comes to the emergency department reporting a few days of excruciating pain in a band around his right chest. Today, he developed vesicles over the same area which prompted him to come in. Classic shingles. Like most patients diagnosed with this disease, he is sent home with wound care, return precautions, contact precautions, antivirals and steroids. But how strong is the evidence for those medications? Do they actually improve pain and/or prevent one of the painful complications of shingles, post-herpetic neuralgia?
An summary of a Cochrane review published in November 2018 (see reference #1 below) looked at 6 randomized controlled trials (5 with acyclovir and 1 with famciclovir versus placebo) to assess incidence of post-herpetic neuralgia up to 6 months post illness in patients taking antivirals versus placebo. Although they did not appreciate a difference when comparing antivirals with placebo at 4 and 6 months, they did note a reduction in reported pain at 1 month in the experimental group (44.1% (153/347) acyclovir and 53.3% (184/345) placebo; RR 0.83, 95% CI 0.71-0.96, p=0.01). And, antivirals did not cause an increase in adverse effects.
Another Cochrane review, also published in November 2018 (see reference #2 below), looked at 5 randomized controlled trials comparing steroid use versus placebo given within 7 days of rash onset in patients with zoster. Unfortunately, they also did not appreciate a decreased incidence of post-herpetic neuralgia in patients receiving steroids, this time at 3, 6 and 12 months out. However, they did note a possible trend towards a reduction in acute pain within the first month and did not appreciate any increased side effects in the steroid group.
Given the lack of adverse effects with both medications, as well as an improvement in pain reported during the acute illness, it is probably still worth it to treat patients presenting with shingles with the usual combo of antivirals and steroids. Unfortunately neither of these appear to be helpful in preventing post-herpetic neuralgia. If you get the chance, remember to stress the importance of prevention by recommending the zoster vaccine to your patients, friends and family over 50.
Click here to read a quick summary of key points about zoster:
https://coreem.net/core/herpes-zoster/
Click here to read more about the CDC recommendations for zoster vaccine:
https://www.cdc.gov/vaccines/vpd/shingles/hcp/shingrix/recommendations.html
References:
1) Antiviral Medications for the Prevention of Post Herpetic Neuralgia after Herpes Zoster Infection. Acad Emerg Med. 2018 Nov 12. doi: 10.1111/acem.13662.
2) Corticosteroids for Preventing Post Herpetic Neuralgia after Herpes Zoster Infection. Acad Emerg Med. 2018 Nov 12. doi: 10.1111/acem.13661.
