Shingles treatment shows 'concerning' variations
Doctor education about herpes zoster ophthalmicus (HZO) – a form of shingles which affects the nerve shared by the eye and its accessory structures—needs improvement, given the incidence of herpes zoster presentations to GPs almost doubling over the past decade.
HZO is caused by reactivation of latent varicella zoster virus, and effects about 10% of herpes zoster patients.
The authors of a research letter published online today by the Medical Journal of Australia found "concerning variations in timing and practice of treating HZO," after analysing data from digital health records of the first 100 consecutive patients who presented to The Royal Victorian Eye and Ear Hospital (Eye and Ear) emergency department with HZO during July 2017—July 2018.
"Sixty-five patients initially presented to their GP, 20 to a hospital emergency department, and 15 directly to the Eye and Ear," wrote the authors, led by Dr. Rahul Chakrabarti, an ophthalmologist at the Eye and Ear.
"The mean time between rash onset and presentation to a GP or emergency department was 3.3 days. For 51 patients, treatment commenced before presentation to the Eye and Ear (famciclovir, 27; valaciclovir, 16; acyclovir, 6; two patients had received no topical treatment); treatment had commenced within 72 hours of the rash developing for 36 of these patients (71%).
"The recommended dose and frequency were prescribed for 16 of the 51 patients. For 29 patients, antiviral therapy was prescribed at lower than the recommended dose or prescribed as a topical treatment; the prescribing information was not documented for five patients.
"Nineteen of the 68 patients who attended follow-up seven to 14 days after their initial presentation to the Eye and Ear presented with ocular symptoms regarded as late complications, including four with more than one complication. Eight of 29 patients (29%) who had not commenced systemic antiviral therapy within 72 hours of rash onset developed late complications, and 13 of 71 patients (18%) who were treated within 72 hours."
The authors wrote that the variations in timing and treatment could have been caused by diagnostic uncertainty caused by the variability of clinical signs during the early stages of HZO, and by an "earlier discrepancy between the famciclovir dosing recommended by therapeutic guidelines (250 mg three times a day) and recommendations based upon the results of a clinical trial (500 mg three times a day)".
"This discrepancy has since been resolved in the therapeutic guidelines."
The authors concluded that the education of all health care professionals involved in the care of patients with HZO "needs to be improved."
"Clinical practice guidelines must provide clear and consistent information about managing HZO."
More information: Rahul Chakrabarti et al. Characteristics, treatment and complications of herpes zoster ophthalmicus at a tertiary eye hospital, Medical Journal of Australia (2020). DOI: 10.5694/mja2.50554