Staphylococcus-associated marginal keratitis secondary to pterygium surgery: a case report

BACKGROUND: Staphylococcus-associated marginal keratitis is an immune-mediated corneal disorder mainly secondary to chronic blepharoconjunctivitis. We report a rare case of Staphylococcus-associated marginal keratitis following pterygium excision. To the best of our knowledge, none of the previous literature has described such an acute complication after pterygium surgery. CASE PRESENTATION: We report a case of a 50-year-old woman who suffered from pterygium in the left eye and underwent pterygium surgery. After surgery, slit-lamp examination showed an incomplete ring-shaped creamy white infiltrate. Corneal pathogenic microbial detection was negative. Staphylococcus aureus was found on the upper eyelid margin of the affected eye. Therefore, she was clinically diagnosed with Staphylococcus-associated marginal keratitis. The infiltrate was gradually absorbed after steroids, topical antibiotics, and lubricant eye drops were administered. After 2 years of follow-up, neither corneal infiltrate nor pterygium recurrence was observed. CONCLUSION: Staphylococcus-associated marginal keratitis is an immune reaction mainly secondary to chronic blepharoconjunctivitis, which usually activates an antigen-antibody reaction with complementary activation and neutrophil infiltration in patients sensitized to staphylococcal antigens. Early detection and treatment is of great importance. Topical steroids are effective and should be initiated early once pathogenic microbial infections are excluded. Although chronic staphylococcal blepharoconjunctivitis is a common disease, ophthalmologists should pay more attention to it to avoid potential complications.