Why are corticosteroids contraindicated early in a corneal ulcer in horses?

• A. They accelerate epithelial healing.
• B. They delay epithelial healing and promote corneal melting or infection.
• C. They have no effect on healing.
• D. They reduce tear production.

Answer: (B)

The healing of a corneal ulcer relies on an active inflammatory and immune response to control microbes, clear debris, and promote epithelial migration and tissue repair. Giving corticosteroids early blunts that essential inflammatory cascade, so epithelial cells migrate and proliferate more slowly, delaying wound closure. It also weakens local immune defenses, allowing infection to persist or worsen. In the stroma, steroids dampen fibroblast activity and collagen synthesis, which can lead to thinning and potential corneal melting, especially when proteolytic enzymes from inflammation and infection are already at play. For these reasons, corticosteroids are avoided in the very early phase of a corneal ulcer in horses; they may be considered later only after infection is controlled and epithelial healing is underway, under careful supervision.