Duration of Nummular Keratitis
Nummular keratitis typically persists for weeks to months after the initial viral infection, with subepithelial infiltrates potentially lasting from several weeks to years if untreated, though most cases show improvement within 6 weeks of acute inflammation with appropriate management.
Natural Course and Timeline
The duration of nummular keratitis varies significantly based on the underlying etiology and treatment approach:
Post-Adenoviral Nummular Keratitis
- Acute phase: The initial adenoviral keratoconjunctivitis typically improves within 5 to 14 days 1
- Chronic nummular phase: Subepithelial infiltrates (nummular keratitis) can develop as a sequela and may persist for weeks to months after the acute infection resolves 1
- Treatment threshold: If vision reduction from nummular keratitis has not improved within 6 weeks after acute inflammation, treatment with cyclosporin A eyedrops should be considered 2
- Long-term persistence: Without treatment, these infiltrates can persist for extended periods, though the exact duration is variable 1
Treatment Response Timeline
- With topical steroids: Cases can clear over a few weeks with appropriate high-potency topical corticosteroid therapy 3
- With intrastromal injection: Combined ganciclovir and depot betamethasone showed sustained improvement over a mean follow-up of 22.90 months, with 85.71% of eyes becoming asymptomatic 3
- Recurrent cases: Some patients experience a chronic course characterized by relapses and remissions, particularly when associated with systemic inflammatory conditions 4
Clinical Considerations
Factors Affecting Duration
- Organism virulence: While the guidelines discuss bacterial keratitis progression rates, nummular keratitis is typically a post-viral inflammatory condition rather than an active infection 1
- Treatment timing: Early intervention with appropriate anti-inflammatory therapy can significantly shorten the disease course 3, 2
- Underlying conditions: Patients with systemic inflammatory diseases (such as Hyper-IgD Syndrome) may experience recurrent attacks requiring systemic immunosuppression 4
Important Pitfalls
- Misdiagnosis risk: Nummular keratitis can be mistaken for other conditions, including fungal keratitis, which requires entirely different management 5
- Steroid use caution: While topical steroids are effective for post-viral nummular keratitis, their use before ruling out infectious etiologies (particularly fungal) can worsen outcomes 5
- Vision-threatening potential: Central or paracentral corneal involvement can cause substantial visual loss through scarring, even after the inflammatory process resolves 1
Follow-up Expectations
- Initial monitoring: Patients should be followed closely during the first 6 weeks to assess response to treatment 2
- Long-term surveillance: Even after resolution, patients may require extended follow-up due to potential for recurrence 3, 4
- Visual recovery: With appropriate treatment, most patients achieve good visual outcomes, though corneal scarring may result in permanent vision reduction if treatment is delayed 4