Post-Streptococcal Nummular Keratitis: A New Clinical Entity

Abstract

Introduction: Pot-streptococcal nummular keratitis is an interstitial keratitis characterized by large infiltrates in the cornea. Its mechanism is probably immuno-allergic. Patients and Methods: We report the first three cases of nummular keratitis related to a post-streptococcal infectious disease and we describe its clinical and tomographic aspect. Results: This is a new clinical entity, characterized by multiple rounded, whitish lesions 0.5 to 3 mm in diameter, located in the stroma. These plaques are made of small infiltrates arranged radially giving a “spoke wheel” appearance. With time, these infiltrates having a greater tendency to confluence and the plaques take on a “currency” appearance resembling those described by “Demmer”. Corneal sensitivity is preserved. Corneal optical coherence tomography (OCT) shows hyper-reflective lesions occupying the entire thickness of the stroma, with a "flying saucer" appearance respecting the corneal epithelium and endothelium with a tendency to confluence, particularly in the anterior stroma. Discussion: This keratitis can be unilateral or bilateral and associated with an inflammatory syndrome, a high titer of ASLO, and a streptococcal infection. Conclusion: Ophthalmologists faced with idiopathic nummular keratitis should consider post-streptococcal syndrome as a possible cause. A search for an increasing titer of ASLO and streptococcal infectious evidence establishes this association.