Concurrent reactivation of varicella zoster virus and herpes simplex virus in an immunocompetent elderly male

utaneous infections by herpes simplex virus (HSV) and variella zoster virus (VZV), both of which belong to the alpha ubfamily of herpes viruses, are relatively common.1 After he primary infection, both HSV and VZV remain latent in he nerve tissue for a lifetime and may reactivate.2 It has een shown that HSV and VZV may remain latent in the same erve ganglion.2 However, simultaneous reactivation of both SV and VZV is rare. Giehl et al. found that 20 (1.2%) out f 1718 patients with clinical herpes viruses infection were nfected with both HSV and VZV.1 A 78-year-old man presented to our dermatology clinic ith multiple painful vesicular lesions located on the left orearm and left hand (C6--8 dermatomes) and left lumar region (T12 dermatome), for four days (Figs. 1 and 2). rior to our observation, the patient had been treated ith topical betamethasone valerate for three days. he patient’s medical history was unremarkable besides hildhood varicella. Laboratory investigations revealed an levated level of C-reactive protein of 1.2 mg/dL, suggesting mild inflammatory reaction; other blood tests, including mmunoglobulin levels, hepatitis B virus, hepatitis C virus, uman immunodeficiency virus, and syphilis serology were ither normal or negative. HSV-1 and VZV-specific IgG were ositive, while IgM HSV and VZV were negative. Real-time olymerase chain reaction (PCR) test detected VZV and HSVDNA in the lesions of the left forearm and left hand, nd VZV DNA in the lumbar lesions. A seven-day course of alacyclovir 1000 mg 8/8 h PO resulted in complete resoluion. HSV and VZV are DNA viruses that share some bioogic attributes but, at the same time, differ significantly; uch differences may explain why concurrent reactivation is

rare. 1,3 In immunocompetent patients, HSV is reactivated several times during life, but VZV reactivation generally occurs only once. 3,4 The likelihood of VZV reactivation increases with age, while HSV recurrences decrease with advancing age, probably due to maturation of the immune response. 1,3 HSV and VZV also differ in their relative capacity to reactivate in response to stimuli that perturb neuronal function. 3,4 HSV appears to be reactivated by predisposing factors such as UV light exposure, trauma, fever, and stress. 3,4 Although reports describe induction of zoster with trauma and radiation, VZV does not consistently reactivate in response to recognizable stimuli. 3,4 Concurrent reactivation of VZV and HSV is possible in both immunocompetent and immunosuppressed patients, although it is more common in the latter group. 1 It may occur at different sites of the body or at the same location, and it appears to be more common in those aged ≥50 years of age. 1 Herpes simplex may precede, present simultaneously with, or follow the zoster skin lesions. Medical treatment should be initiated as in the zoster protocol. 2 We report a case of concurrent reactivation of VZV and HSV in an immunocompetent elderly male with no clinical history of herpes simplex but with serologic evidence of past infection. The combination of high sensitivity and specificity, low contamination risk, and speed has made  real-time PCR technology an excellent testing method for diagnosing many infectious diseases. The closed system for amplification and detection used with real-time PCR virtually eliminates amplicon contamination. 5 Furthermore, the target gene for HSV and VZV detection are different, eliminating the possibility of cross-over reaction. 5 In this clinical case, the results by real time PCR were strongly positive, and after repetition, they confirmed the result. The PCR test allowed detection and identification of the viral DNA; this knowledge may contribute to the understanding of the pathophysiology of these latent infections.
Simultaneous infection with VZV and HSV was suspected due to the atypical clinical presentation. Dermatologists must be aware of this possibility to assure the correct diagnosis is obtained and that the appropriate treatments are performed.

Financial support
None declared.

Author's contributions
Miguel Costa-Silva: Approval of the final version of the manuscript; conception and planning of the study; elaboration and writing of the manuscript; obtaining, analyzing and interpreting the data; effective participation in research orientation; intellectual participation in propaedeutic and/or therapeutic conduct of the cases studied; critical review of the literature; critical review of the manuscript.
Joana Sobrinho-Simões: Approval of the final version of the manuscript; conception and planning of the study; effective participation in research orientation; intellectual participation in propaedeutic and/or therapeutic conduct of the cases studied; critical review of the manuscript.
Filomena Azevedo: Approval of the final version of the manuscript; conception and planning of the study; intellectual participation in propaedeutic and/or therapeutic conduct of the cases studied; critical review of the manuscript.
Carmen Lisboa: Approval of the final version of the manuscript; conception and planning of the study; effective participation in research orientation; intellectual participation in propaedeutic and/or therapeutic conduct of the cases studied; critical review of the literature; critical review of the manuscript.