Clinical Diagnosis of Herpes Zoster in Family Practice

Abstract

PURPOSE Family physicians usually diagnose herpes zoster on clinical grounds only, possibly resulting in false-positive diagnoses and unnecessary treatment. We wanted to determine the positive predictive value of the physicians' judgment in diagnosing herpes zoster and to assess the applicability of dried blood spot analysis for diagnosis of herpes zoster in family practice.METHODS Our study population consisted of 272 patients older than 50 years with herpes zoster (rash for less than 7 days). Dried blood spot samples were collected from all patients and sent by mail to the laboratory. Baseline measurements included clinical signs (localization, severity, and duration of rash) and symptoms (duration and severity of pain). Varicella-zoster virus antibodies were determined at baseline and 5 to 10 days later. Multivariate logistic regression was used to assess independent associations between clinical variables and serological confi rmation of herpes zoster.RESULTS Dried blood spot analysis was possible in 260 patients (96%). In 236 the diagnosis of herpes zoster was confi rmed serologically (positive predictive value of clinical judgment 90.8%; 95% confi dence interval, 87.3%-94.3%). Independent clinical variables for serologically confi rmed herpes zoster were severity and duration of rash at fi rst examination.CONCLUSION Family physicians have good clinical judgment when diagnosing herpes zoster in older patients. Dried blood spot analysis is a logistically convenient method for serological investigation of patients in family practice, but it is rarely needed for diagnosing herpes zoster. INTRODUCTIONH erpes zoster is a common disease, with a reported incidence varying from 2.2 to 4.8 per 1,000 persons per year. [1][2][3] It is due to a localized recrudescence of the varicella-zoster virus in sensory ganglia, where the virus has remained dormant since the primary infection (chickenpox). Age and immunity-attenuating diseases are well-known risk factors for herpes zoster. 4 The most frequent complications of herpes zoster include postherpetic neuralgia and, in cases of ophthalmic herpes zoster, sight-threatening eye problems.Because the typical unilateral rash helps family physicians diagnose herpes zoster clinically, suspected cases of herpes zoster are rarely investigated serologically or virologically. False-positive diagnosis of herpes zoster, however, is reported to occur in up to 13% of patients 5,6 and may result in unnecessary prescription of antiviral medications, erroneous referral, and unnecessary invasive interventions for the prevention of postherpetic neuralgia. 7 Serological analysis is one method to confi rm the diagnosis of herpes zoster, 8 but few studies have assessed its value in family practice. Moreover, such analysis in primary care can be fraught with logistic problems. In remote areas laboratory facilities may not be accessed easily, and for research purposes uniform analysis techniques at a central location may 306CLINIC A L DIAGNOSIS OF HER PES ZOS T ER be preferred over analy...

Sociodemographic characteristics and chronic medical conditions as risk factors for herpes zoster

“…Family physicians have good clinical judgment with regard to diagnosing HZ, and clinical diagnosis is confirmed serologically in 91% of patients older than 50 who have HZ. 53 Another potential limitation is that any patients with HZ who went to a private practitioner might not have been detected in our study, leading to an underestimate of the disease. However, this proportion of patients would be small given the public health care provision in Spain, as well as the availability of subsidized drugs for the treatment through primary care.…”

17. Herpes Zoster and Post‐Herpetic Neuralgia

“…However, in 10% to 20% of the cases, it turns out that the clinical diagnosis of herpes zoster cannot be confirmed with serology or PCR. 7,8 The distinction from herpes simplex is somewhat difficult in young people. In contrast to herpes zoster, with herpes simplex, the rash can cross the midline of the body, and the symptoms can relapse.…”

Inequalities in zoster disease burden: a population-based cohort study to identify social determinants using linked data from the U.K. Clinical Practice Research Datalink

“…However, the methods used in this study are based on our previously developed methodology for ascertainment of social factors among older individuals using linked CPRD data, which found prevalence of factors such as ethnicity, living alone, cohabitation and care home residence comparable with the 2011 English Census, whereas being an immigrant was under‐represented in these data . In the U.K., zoster is mainly diagnosed clinically; however, a clinical diagnosis of zoster in primary care is reported to have a high (91%) positive predictive value among older individuals . Any misclassification of exposure or outcome is likely to be nondifferential, tending to bias effect estimates towards the null.…”