Herpes zoster and COVID-19 infection: a coincidence or a causal relationship?

The first cases of COVID-19 were reported in Wuhan, China, in December 2019. Skin manifestations of COVID-19 vary, among which herpes zoster has recently been found to be associated with the infection. We studied the available literature regarding COVID-19-associated herpes zoster (HZ). We searched the PubMed and Scopus databases for available literature till 20th of May 2021 using the following terms: 'Herpes zoster' or 'Varicella zoster virus' and "COVID-19" or "coronavirus disease" or "SARS-CoV-2". This search revealed 87 publications, of which 29 articles met the inclusion criteria. A total of 29 patients had HZ associated with COVID-19 infection. The patients' ages ranged from 7 to 82 years, averaging 56 years. Thirteen patients (45%) were men and 16 (55%) women. We summarized the demographic data, clinical data, comorbidities, treatment used, lymphocyte count, and distribution and timeline of HZ rash in COVID patients. Lymphopenia was prevalent in 86.6% of patients (where lymphocyte data were available). We discuss possible causes of HZ due to COVID-19. More and larger studies are needed to confirm any relationship between these two infections; however, this study may pave the way for similar studies on this topic.