Though more research is needed, reactivation of the varicella-zoster virus may be caused by a decrease in absolute lymphocytes caused by COVID-19.
Researchers in Italy have published a letter suggesting there may be a link between necrotic zoster and coronavirus disease 2019 (COVID-19).
The authors noted that although the number of positive COVID-19 cases seemed to have peaked in Italy at the time of their writing, little is known about the cutaneous manifestations of the virus. They observed 4 cases of simultaneous zoster and COVID-19 cases between March and April 2020, including 3 women and 1 man with a median age of 70.5 years. Three of the patients were admitted to intensive care and required mechanical ventilation.
All 3 patients developed a necrotic herpes zoster on the second branch of the trigeminal nerve, according to the letter. The male patient also had a previous heart transplant and developed classic herpes zoster symptoms. Despite the immunosuppressive drugs he required, the authors said he showed a more indolent case of COVID-19 and did not require hospitalization.
At the time of their diagnosis, the authors said all 4 patients showed leukopenia. Following their diagnoses, treatment with acyclovir began along with analgesics.
Other investigators have also reported patients with a skin rash following COVID-19, ranging from erythematous rash to a chicken pox-like eruption, according to the letter. In their observations, the researchers found 2 clinical manifestations, including the necrotic herpes zoster of the trigeminal nerve and the classic manifestation. In all of the cases, treatment with acyclovir resolved lesions after 10 days and they saw no postherpetic neuritis.
Typically, the authors said necrotic herpes zoster is most commonly found in HIV-positive patients or in those with iatrogenic immunosuppression, though none of the 4 patients were HIV-positive and only 1 had a history of immunosuppressive drug intake. The researchers said it was surprising that the patient with a history of immunosuppression exhibited the less severe case of herpes zoster.
Although more research is needed as it relates to COVID-19, the authors suggested that a possible explanation for reactivation of the varicella-zoster virus may be a decrease in absolute lymphocyte number due to infection with the severe acute respiratory coronavirus 2, which causes COVID-19. All 4 patients showed a decrease in CD3+ and CD8+ elements in their circulating blood prior to the onset of herpes zoster.
Tartari F, Spadotto A, Zengarini C, Zanoni R, et al. Herpes zoster in COVID-19-positive patients. International Journal of Dermatology; June 12, 2020. https://onlinelibrary.wiley.com/doi/full/10.1111/ijd.15001. Accessed September 22, 2020.