Why do so many clinicians believe that recurrent zoster is common?
The University of Washington Department of Medicine, Division of Dermatology, Seattle WA, 98195. firstname.lastname@example.org
It is my clinical experience that recurrent zoster is not so rare. Such is the unanimous opinion of more than a half dozen peer reviewers and journal editors who have summarily dismissed our attempts in the past 2 years to address the issue of recurrent zoster in immunocompetent individuals. Recurrent zoster, they contend, is not reported in the literature because it is a commonplace occurrence. Is that really the case?
Articles dating back to 1900 purport cases of recurrent zoster, but most of these reports predated routine laboratory testing for varicella zoster virus (VZV), which was first cultured from herpes zoster lesions by Weller and Stoddard in 1952. In 1965 Hope-Simpson published a review of 192 cases of herpes zoster seen in a 16-year period in Cirencester England, classifying 8 of 192 as second-attacks and 1 of 192 as a third attack . However, reports as early as 1950 noted that HSV could clinically imitate herpes zoster . Ironically, there are actually more laboratory-confirmed cases of misdiagnosed recurrent zoster in the literature than there are of actual recurrent zoster in immunocompetent patients. Heskel and Hanifin described three patients initially diagnosed with recurrent herpes zoster, but all with HSV by culture, again raising the question as to whether earlier cases of recurrent zoster represent instead misdiagnosed cases of HSV .
In patients with HIV infection, several reports have documented chronic infection with VZV, manifesting both as disseminated varicella as well as persistent or recurrent zosteriform lesions. However, even the absence of HIV, the clinicians with whom we've discussed this issue are nearly universal in their view that recurrent zoster is not uncommon. A recent study on the prevention of zoster with VZV vaccination enrolled 38,546 immunocompetent patients, of whom 1308 were diagnosed with herpes zoster, and 3 were subsequently diagnosed with recurrent zoster . This large study, even with the assumption that these three cases were true recurrences despite the absence of laboratory confirmation, suggests that clinicians would need to see a very large number of zoster cases before encountering a true recurrence.
We saw a 67 year-old female patient with a 4-year history of actinic reticuloid treated intermittently using varying doses of oral prednisone over that time period. Over the next 5 months, she developed three separate episodes of a vesicular eruption along the L3-L4 dermatome that resolved with valacyclovir therapy. Upon her third visit, laboratory testing confirmed VZV by a positive fluorescent antibody (FA) test and a positive viral culture, making her a true case of recurrent zoster. Laboratory-confirmed cases of recurrent zoster in immunocompetent individuals are rare in the literature. In 2004 Nikkels and colleagues presented a 5-year-old male with two episodes of herpes zoster occurring fifteen months apart in separate dermatomes (S2-3, then C6), with both outbreaks confirmed by FA positivity for VZV . To our knowledge, there are no other laboratory confirmed cases of cutaneous zoster recurrence in immunocompetent individuals, although there are rare cases reported in the ophthalmology literature without cutaneous findings.
Our patient was on prednisone, a well-recognized risk for getting herpes zoster, because VZV reactivation is related in part to the state of cell-mediated immunity. Despite the large number of patients on immunosuppressive medications like prednisone, there are no reports documenting increased risk of recurrent or persistent herpes zoster in this population like there is with the HIV population. While patients with hematologic malignancies exhibit higher rates of herpes zoster, increased rates of recurrent herpes zoster have not been reported in this population either.
From the standpoint of infective transmissibility, there are different implications for herpes zoster and HSV-mediated zosteriform simplex. With the exception of persons who have not had chickenpox or those who are severely immunosuppressed, exposure to a patient with herpes zoster poses no proven infectious risk. On the other hand, there is considerable literature regarding the non-venereal transmission of HSV, including well-described entities such as eczema herpeticum and herpes gladiatorum. Live HSV virus has been isolated from inanimate surfaces, common household objects, medical charts, and even in hot tubs from spa facilities . Without clear distinction between true recurrent zoster and HSV-mediated zosteriform simplex, both patients and their future contacts may be inadequately educated regarding the precautions needed to prevent viral transmission.
A colleague in internal medicine spoke to us about a case of recurrent zoster in her clinic. This patient was seen by several different physicians who all concluded with the diagnosis of recurrent zoster. After seeing our review of the literature, she subsequently performed laboratory testing on this patient and confirmed the diagnosis of HSV-mediated zosteriform simplex. There are several other patients in their clinic who are also thought to have "recurrent zoster". We predict that laboratory testing of these patients will confirm what is already demonstrated by the evidence at hand: recurrent zoster in the immunocompetent is an extremely uncommon event.
References1. Hope-Simpson RE. The nature of herpes zoster: a long-term study and a new hypothesis. Proc R Soc Med 1965; 58: 9-20.
2. Slavin HB and Ferguson Jr JJ. Zoster-like eruption caused by the virus of herpes simplex. Am J Med 1950; 8: 456-67.
3. Heskel NS and Hanifin JM. Recurrent zoster: an unproven entity? J Am Acad Dermatol. 1984; 10(3):486-90.
4. Oxman MN et al. A vaccine to prevent herpes zoster and postherpetic neuralgia in older adults. N Engl J Med 2005; 352(22): 2271-84.
5. Nikkels AF, Nikkels-Tassoudji N and Pierard GE. Revisiting childhood herpes zoster. Pediatr Dermatol. 2004; 21(1): 18-23.
6. Nerurkar LS, West F, May M, Madden DL, Sever JL. Survival of herpes simplex virus in water specimens collected from hot tubs in spa facilities and on plastic surfaces. JAMA. 1983 Dec 9; 250(22):3081-3
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