Occurrence of Common Allergic Diseases in Children with Idiopathic Nephrotic Syndrome

BACKGROUND Clinical and immunological studies have consistently shown a possible link between atopy and idiopathic nephrotic syndrome (INS). However, whether allergic diseases occur after INS develops is unknown. METHODS From Taiwan's National Health Insurance database, 1340 children with newly diagnosed INS and 5360 non-INS matched controls were identified in 2000-2007. By the end of 2008, the incidences and hazard ratios of four allergic diseases (allergic conjunctivitis, allergic rhinitis, atopic dermatitis, and asthma) were calculated. RESULTS The incidence rates of all four allergic diseases were greater in the INS cohort than in the non-INS cohort in all age groups and decreased sharply as age increased in both cohorts. Children with INS had the highest adjusted hazard ratio (4.13; 95% confidence interval [CI], 2.50-6.83) for atopic dermatitis and the lowest adjusted hazard ratio (1.71; 95% CI, 1.39-2.09) for allergic rhinitis. Most of the allergic diseases appeared within 2-6 months after INS developed, and the incidences declined with increasing follow-up duration. CONCLUSIONS Allergic disorders are common in children with INS, especially within the first year after diagnosis. The role of INS in the development of allergic disorders should be elucidated to establish innovative disease intervention programs.