PURPOSE: The purpose of this study was to examine the incidence of ocular, periocular, and systemic inflammatory conditions among patients with pterygium and assess if these conditions are risk factors of pterygium development. METHODS: A case-control study was conducted using electronic medical records from Clalit Health Services in Israel between 2002 and 2022. Patients diagnosed with pterygium were included
for each case, 3 controls were matched based on birth year, sex, and ethnicity. Mixed models were used to assess differences in the groups' demographic characteristics of ocular and systemic diseases. Generalized estimating equation logistic regression was used to estimate the odds ratios (ORs) and adjust for confounders. RESULTS: A total of 94,652 patients diagnosed with pterygium and 378,608 matched controls were included in the study. The average age of patients with pterygium was 53 ± 16 years
54% were male. A significant association was found between pterygium and vernal keratoconjunctivitis (OR 2.12, 95% confidence interval [CI], 1.90-2.36), chronic allergic conjunctivitis (OR 1.69, 95% CI 1.58-1.82), blepharitis (OR 1.66, 95% CI 1.61-1.70), and chalazion (OR 1.27, 95% CI 1.23-1.33). A significant association was also found between pterygium and systemic conditions as unspecified systemic allergy (OR 1.08, 95% CI 1.04-1.13), asthma (OR 1.08, 95% CI 1.04-1.11), and atopic dermatitis (OR 1.14, 95% CI 1.08-1.19). CONCLUSIONS: Various inflammatory and allergic diseases-ocular, periocular, and systemic-increase the risk of pterygium. Further research is needed to investigate the role of inflammation in pterygium development.