HSV Dendritic Ulcer
Caused by Herpes Simplex Virus, a double stranded DNA virus
Accounts for 50-80% of ocular HSV
Starts as small, raised, intraepithelial vesicles→ vesicles coalesce → linear branching dendrites→ amorphous geographic ulcer
It occurs due to active proliferation of the live virus.
Dendrites
Multiple small, linear, branching epithelial dendrites on the corneal epithelium
Borders are slightly raised, grayish
Central ulceration
Possess terminal bulbs and swollen epithelial borders containing the live virus
Several dendrites may coalesce to form a geographic epithelial ulcer (especially in immunocompromised patients and inappropriate use of topical steroids)
Staining
Rose bengal - stains the devitalized cells and live herpes virus at the edge of the ulcer
Fluorescein - stains the base of the central ulcer
The virus moves from cell to cell, so each lesion develops one cell at a time. There are cells falling out and virus cells filling in giving rise to the linear pattern.
Topical antiviral agents are used in the treatment of HSV dendritic ulcers.
Dendrites should be distinguished from Pseudodendrites
Consist of swollen poorly adherent epithelial cells usually seen in the corneal periphery
They lack terminal bulbs and dichotomous branching
Stain poorly with fluorescein and rose bengal
Secondary to :
Herpes Zoster
Contact lens wear
Recurrent corneal erosions from corneal dystrophies
Image from Rajan Eye Care Hospital