Even in a relatively asymptomatic case of COVID-19, it is possible that the virus could have fostered retrograde reactivation of the varicella-zoster virus.
Although coinfections with coronavirus disease 2019 (COVID-19) and herpes zoster have been sparsely reported, a new case study suggests that the emergence of a latent varicella-zoster virus (VZV) might be enabled by the inflammatory response to COVID-19.
In the case study, published in the European Journal of Neurology, a 39-year-old immunocompetent man presented with mild COVID-19, which evolved into herpes zoster infection on the left side of his face. He reported having chickenpox as a child but had no history of recurrent or opportunistic infections or use of immunosuppressive drugs.
In the 10 days before being admitted to the emergency department (ED), the patient had noticed fatigue and had experienced occasional episodes of diarrhea, followed by left trigeminal neuralgia. Three days after noting the neuralgia, the patient reported a low fever, at which point he visited the ED. He still had no visible skin lesions and was discharged with treatments for his symptoms, although by the end of the day a papulovesicular rash had emerged.
An assistant physician prescribed oral acyclovir and pregabalin, but the patient saw no improvement, so he returned to the ED 2 days later. Once admitted to the hospital, he was treated with intravenous acyclovir and physicians noted significant clinical improvement after 24 hours.
According to the study authors, the patient’s medical history showed that he could have been exposed to COVID-19 on 2 different occasions. Based on this and the current pandemic, a nasopharyngeal test was conducted and showed a positive result.
The investigators noted that VZV tends to remain latent, although it can be reactivated following stress conditions such as a viral infection. In the present case, the physicians hypothesized that the infection with COVID-19 might have been the stress factor. Reactivation of herpes zoster affects the sensory ganglion and its cutaneous nerve.
Other researchers have already noted evidence of a cytokine storm resulting from severe COVID-19, and even in a relatively asymptomatic case, it is possible that the virus could have fostered retrograde reactivation of VZV. Based on their findings, the authors concluded that COVID-19 could cause the rare presentation of herpes zoster.
Ferreira A, Romao T, Macedo Y, Pupe C. COVID-19 and herpes zoster co-infection presenting with trigeminal neuropathy. European Journal of Neurology; May 24, 2020. https://onlinelibrary.wiley.com/doi/full/10.1111/ene.14361. Accessed October 28, 2020.