Figure 1. This 36-year-old man’s slit lamp finding was associated with a “scratchy” eye and a recent emergency department diagnosis. Can you identify it?
A 36-year-old soft contact lens wearer presented to the emergency department with pain and a rash on the left side of his face. There, he was diagnosed with herpes zoster and prescribed 1000 mg valacyclovir to be taken 3 times a day for 7 days. Two days after initiating treatment, he reported to the eye clinic because his left eye felt “scratchy.” He had stopped all contact lens wear 2 days earlier An examination with a slit lamp discovered the finding in Figure 1.
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A patient with varicella-zoster virus (VZV) may have corneal involvement which can cause punctate or a dendritic like epithelial keratitis. The dendrite like appearance is called a pseudodendrite. It consists of heaped up thickened epithelial cells. These pseudodendrites have corneal findings that can be differentiated clinically from the herpes simplex virus (HSV) dendrite by the following features: They stain with fluorescein to swollen adherent epithelial cells. They do not cause a bright deep stromal stain, as does the HSV, because they do not get into the stroma. They are linear and elevated. They lack true branching. They do not have terminal bulbs. They do not grow or change in size rapidly, as do true HSV dendrites. The use of topical steroids does not make them worse, where as it will make HSV dendrites worse.1,2
They are also distinct from herpes simplex dendrites, which usually have more stromal involvement.
This patient’s pseudodendrite resolved after 1 week with a topical lubrication, dosed 4 times a day during the day in drop form and an ointment before bed.
Late-appearing herpes zoster pseudodendrites more commonly occur in patients younger than 60 years old, and in immunocompromised individuals.2,3
“Younger patients had more episodes of delayed pseudodendritiform keratitis and flares of inflammation compared with older patients, who had more problems related to neurotrophic keratopathy,” according to a 2011 study in Ophthalmology.
Patients who do not respond to lubricant drops and ointments can be treated using topical 0.15% gancyclovir 5 times a day for 1 week, with a taper for the following 2 weeks.2
Matthew Garston, OD, is an adjunct professor at the New England College of Optometry and was a senior staff optometrist in the medical department at MIT for 43 years.
1. Piebenga LW, Laibson PR. Dendritic lesions in herpes zoster ophthalmicus. Arch Ophthalmol. 1973;90(4):268-270. doi:10.1001/archopht.1973.01000050270002
2. Aggarwal S, Cavalcanti B, Pavan-Langston D. Treatment of pseudodendrites in herpes zoster ophthalmicus with topical ganciclovir 0.15% gel. Cornea. 2014;33(2):109-113. doi:10.1097/ICO.0000000000000020
3. Ghaznawi N, Virdi A, Dayan A, et al. Herpes zoster ophthalmicus: comparison of disease in patients 60 years and older versus younger than 60 years. Ophthalmol. 2011;118(11):2242–2250. doi:10.1016/j.ophtha.2011.04.002