Patients with herpes zoster ophthalmicus are missing their antiviral treatment window by waiting three or more days to seek medical attention after a rash appears, research has shown.
A research letter published this month in the MJA, says there are concerning variations in the timing and treatment of herpes zoster ophthalmicus, despite recognised clinical guidelines.
The study authors performed a retrospective audit on the digital health records of 100 patients who presented consecutively at an Australian tertiary eye hospital between July 2017 and July 2018 with herpes zoster ophthalmicus.
The average age of patients included in the study was 59 years and the study authors assessed each record for clinical presentation, complications, and treatment practice.
GPs were the first point of treatment for 65% of the patients in the study, while 20% first presented to a hospital emergency department and the remaining 15% directly to the Royal Victorian Eye and Ear Hospital.
“Our findings suggest that education of all healthcare professionals involved in the care of patients with herpes zoster ophthalmicus needs to be improved,” the study authors say.
Only half of all patients were found to have begun antiviral treatment prior to presenting at the eye hospital. And of these patients who had started treatment, only 71% had been initiated on the antiviral medication within 72 hours of their rash developing.
This delayed treatment was despite advice in the therapeutic guidelines which recommends any antiviral treatment to be initiated within three days for it to be effective.
Dosage was also a problem among patients who received prior treatment, with only 31% prescribed the recommended dose of:
- famciclovir, 500mg, three times a day;
- or valaciclovir, 1g, three times a day;
- or acyclovir, 800mg, five times a day.
The variability in treatment could be partly explained by an earlier discrepancy where the famciclovir dosing recommended in the therapeutic guidelines was only half of that recommended in the results of a clinical trial.
But Associate Professor John Litt, a recently retired GP academic and public health physician, commenting on the study, said it was important to be on the lookout for the ocular emergency of ophthalmic zoster and remember to refer these patients to an ophthalmologist for review.
“It’s very difficult to treat ophthalmic zoster and the best prevention is to vaccinate the at-risk group and, if treatment is required, to administer antivirals early (within the first 72 hours from rash onset) and at the recommended dose,” he said.
Part of the challenge of administering effective treatment was also attributed to low public awareness of the importance of seeing a GP sooner, rather than later, if they suspect they might have shingles.
“Often people with zoster have a lot of pain and that’s often the reason they present to the GP,” Professor Litt said.
To improve early intervention for ophthalmic zoster, patients suspected of having shingles on the face could be examined for any ulcers on the eye with an ophthalmoscope, Professor Litt said.
But one of the most important strategies to prevent shingles complications such as ophthalmic zoster and postherpetic neuralgia was ensuring a high uptake of Zostavax in patients aged 70 years and older he said.
“Patients 70-79 years are able to get Zostavax under the national immunisation program and when they come to get their annual flu shot, it could be the perfect time to offer them Zostavax, administered in the other arm,” he said.
MJA 2020, 20 April