Take-home message: Pediatric herpes simplex virus should be part of the differential diagnosis when a patient has unilateral recurrent disease in the anterior segment.
By Lynda Charters; Reviewed by Kathryn Colby, MD, PhD
—Pediatric herpes simplex virus is an important disease in children, a high percentage of whom have stromal disease. The disease is associated with a high risk of recurrence and a risk of induced astigmatism from corneal scarring and reduced vision, said Kathryn Colby, MD, PhD.
“[Treatment with] oral acyclovir is safe, although not FDA-approved for use in children,” said Dr. Colby, associate professor of ophthalmology, Harvard Medical School, Boston, and director, Pediatric Cornea Service, Boston Children’s Hospital. “The dose of acyclovir must be adjusted with growth in children.”
Strategy for case management
Dr. Colby recounted the case of a 4-year-old girl from Bermuda with recurrent red eye in the right eye only since 8 months of age. She had been treated multiple times with topical antibiotics and steroids, but the disease continued to recur. Previous diagnoses included staphylococcal marginal disease, limbal vernal keratoconjunctivitis, and phlyctenular keratoconjunctivitis.
In handling this case, Dr. Colby first considered the relevant historical patient information, such as familial corneal disease, systemic allergies or atopy, and duration and frequency of episodes. The child had no history of systemic allergic disease.
Examination showed extensive corneal neovascularization and swelling at the inferior limbus in the affected eye. Peripheral anterior stromal footprints,and mild blepharitis were seen, but no giant papillary conjunctivitis or limbal follicles were noted on clinical exam. The contralateral eye was normal.
Next, Dr. Colby measured the corneal sensation, which was decreased in the affected eye.
The working diagnosis was recurrent herpes simplex keratitis. The clinical findings and history did not support the previously entertained diagnoses listed above.
The patient was started on a treatment of oral acyclovir, which, in children, is an off-label use of this medication. Taken into consideration were the patient’s history of recurrent unilateral disease, decreased corneal sensation, and anterior stromal footprints.
“Her mother noted an almost immediate improvement,” Dr. Colby said.
However, another ophthalmologist stopped the acyclovir treatment because of the improved clinical picture. The symptoms recurred almost immediately.
Dr. Colby restarted the acyclovir treatment and also began low-dose prednisolone acetate 0.12% to help with the corneal vascularization and azithromycin applied to the eyelashes for blepharitis.
“The neovascularization regressed over several months with no recurrences,” Dr. Colby said.
Once the child’s symptoms were stable, Dr. Colby was able to taper the topical steroid therapy. The child completed a 1-year course of a prophylactic dose of acyclovir and symptoms remained “quiet” without further recurrences.
Factors to keep in mind
“Herpes simplex virus is a very important common disease in children,” she said. “The end result of stromal herpes simplex virus is a scarred vascularized cornea. We know that pediatric herpes simplex keratitis has an 80% risk of recurrence, a 75% risk of stromal disease, and a 30% rate of misdiagnosis.”
Dr. Colby added that 80% of children with herpes simplex keratitis develop scarring, mostly in the central cornea. However, the induced irregular astigmatism accompanying bouts of stromal keratitis is an even more clinically relevant factor in these patients.
Twenty-five percent of children have more than 2 D of astigmatism, most of which is irregular. Visual acuity is less than 20/40 in about 25% of children and 60% of children have reduced corneal sensation.
Acyclovir is well tolerated by pediatric patients, but Dr. Colby advised that ophthalmologists be aware of lactose intolerance. The drug has a wide therapeutic and safety index.
Dr. Colby prescribes 100 mg of acyclovir twice daily as prophylaxis for very young infants, 200 mg twice daily for toddlers, 300 mg twice daily for children older than toddlers, and 400 mg twice daily for older children. When a child presents with acute infectious herpes simplex virus, she prescribes the same number of milligrams three-times daily based on age and weight.
“When treating children with topical steroids, tapering of the drugs should be done slowly, over a long period,” Dr. Colby said. “Management of amblyopia is key.
“Always consider pediatric herpes simplex virus when a patient has unilateral recurrent disease in the anterior segment, with awareness of the protean manifestations of this virus,” she concluded.
Kathryn Colby, MD, PhD
E: [email protected]
This article was adapted from. Dr. Colby’s presentation during Pediatric Subspecialty Day at the 2014 meeting of the American Academy of Ophthalmology. Dr. Colby has no financial interest in any aspect of this report.