Various infections in patients with autoimmune bullous diseases: a retrospective case-control study

Background: Infection will cause adverse outcomes in autoimmune bullous diseases (AIBD). We aimed to analyze pathogen spectrum and location characteristics of infection in AIBD, risk factors of infection and provide probable suggestion to infection prevention. Methods: : This is a retrospective case-control study on medical records of inpatients diagnosed as AIBD in Huashan Hospital from 2017 to 2021. Results: : A total of 263 patients diagnosed with AIBD were enrolled. Total infection rate was 42.2%. Infection rate was 52.1% in pemphigus and 30.6% in bullous pemphigoid.Of patients with infections, 49.5% had bacterial infections, 13.5% had fungal infections, 2.7% had virus infection and 34.2% had mixed infections. 17.1% patients had localized infections and 24.7% had systemic infections. The most common pathogens were Staphylococcus aureus and Candida in localized infection, and were Cryptococcus and Candida in systemic infection. In multivariate logistic model, pemphigus compared to bullous pemphigoid (OR=2.56, 95% CI 1.41-4.63), hypoalbuminemia (OR=3.78, 95% CI 1.68-8.50) and systemic glucocorticoids treatment (OR=4.67, 95% CI 2.51-8.68) were infection risk factors. Bullous pemphigoid compared to pemphigus (OR=3.99, 95% CI 1.03-15.45), high dose systemic glucocorticoids treatment compared to low (OR=19.31, 95% CI 3.32-112.28) or medium dose (OR=5.71, 95% CI 1.37-23.79) were risk factors of systemic infection in infected patients with systemic glucocorticoids treatments. Conclusions: : Infection rate in AIBD patients was high. Pathogen spectrum and location of infection were broad. Systemic glucocorticoid treatment, especially with high dose in previous 3 months had been shown as an important risk factor of infection.