Lyme disease is rarely associated with development of scleritis in endemic areas, with an estimated incidence of 0.2 per 1,000,000 population (95% CI 0, 0.4) in the Baltimore Metropolitan Area, according to research published in the American Journal of Ophthalmology.
Researchers collected data from multiple online databases to estimate the incidence of Lyme disease scleritis in the Baltimore Metropolitan area. Patients with scleritis and Lyme disease were identified from the Wilmer Eye Institute and the Centers for Disease Control and Prevention (CDC). They identified 980 cases of scleritis between January 1, 2012 and December 31, 2020. Of those, 6 scleritis cases developed from a Lyme disease infection, accounting for 0.6% of the participants (average age 43 years (range 24 to 81 years), 4 patients were men, 5 were White). The researchers also report that 0.052% of patients diagnosed with Lyme disease in this study developed scleritis. When examining the entire population of Baltimore, researchers estimated the incidence of all Lyme disease is approximately 3 per 1,000,000 per year, while the estimated incidence of Lyme scleritis is 0.2 per 1,000,000 population (95% CI 0, 0.4). All participants’ symptoms were resolved in a median of 39.5 days (range 29 to 57 days) using antibiotics. All but a single patient were treated with a 28-day course of doxycycline 128 mg twice a day (only 1 patient was switched to cefuroxime 500 mg twice a day due to a gastrointestinal reaction).
This study exemplifies how rare Lyme scleritis is, even in endemic areas such as Baltimore.
The study was limited by its small sample size, a lack of standardized tick surveillance by the CDC, a simultaneous population increase in the Baltimore area that occurred alongside the increase in diagnosis, the sole use of the Wilmer Eye Institute to identify cases of Lyme scleritis, and the consideration that Baltimore is a Lyme disease endemic area and the results may not be generalized to nonendemic areas.
“In the past, the pathogenesis of Lyme disease scleritis has been debated as to whether it is due to direct infection or due to a secondary immune-mediated process. In the initial case report describing Lyme disease scleritis, the scleritis recurred after treatment and was associated with optic neuritis, suggesting the possibility that this was an immune-mediated process,” researchers speculate.
Berkenstock MK, Long K, Miller JB, Burkholder BB, Aucott JN, Jabs DA. Scleritis in Lyme disease. Am J Ophthalmol. Published online May 2, 2022. doi:10.1016/j.ajo.2022.04.017