Salmon patch appearance of the cornea is associated with syphilitic infection.
It is due to the deep vascularization of the cornea, consisting of a radial bundle of brush-like vessels.
- Syphilitic keratitis is non-ulcerative interstitial keratitis that typically manifests as a late sequela of congenital or acquired syphilis.
- The deep stroma of the cornea is primarily involved in syphilitic keratitis and manifests clinically as a stromal haze or focal infiltrates.
- The inflammation appears most commonly in the superior cornea and can lead to corneal thickening.
- Neovascularization of the cornea often occurs after the onset of stromal haze and edema.
- Neovascularization occurs as extensions of both the limbal and anterior ciliary vessels often coinciding with increased lymphatic extension into the peripheral cornea.
- The combination of neovascularization and lymphatic extension leads to the classic salmon-colored patch seen in the disease.
Stages of interstital keratitis in congenital syphilis:
-Initial progressive: Ground-glass appearance
– Florid stage: Salmon patch appearance
-Stage of regression: Ghost vessels.