Abstract: 【Abstract】 Objective To analyze the prevalence of and risk factors for infections in patients with pemphigus, and to evaluate their effect on prognosis. Methods Clinical data were collected from 182 inpatients with pemphigus in Department of Dermatology, Xijing Hospital, Fourth Military Medical University from May 2011 to May 2017, and retrospectively analyzed. Associations of infection rates with age, disease severity, comorbidities, maximum dose of glucocorticoids, hospitalization duration and costs were analyzed. Statistical analysis was carried out with SPSS 22.0 software by using Logistic regression analysis for analyzing risk factors for concurrent infections in pemphigus patients who were hospitalized for the first time. Results Among the 182 patients, 82（45.05%） experienced infections. Additionally, 107 pathogenic strains were cultured from secretions from skin lesions of 77 patients, including 60 strains of Staphylococcus aureus （56.07%）, and 58 Staphylococcus aureus strains were resistant to penicillin （96.67%）. Among the 182 patients, infections were observed in 11 of 14 patients with hypoproteinemia, 69 （41.07%） of 168 patients without hypoproteinemia, 4 （4.81%） of 27 patients with mild pemphigus, 34 （37.7%） of 90 patients with moderate pemphigus and 44 （67.69%）of 65 patients with severe pemphigus. Logistic regression analysis showed that the prevalence rate of infections was significantly higher in the patients with hypoproteinemia than in those without hypoproteinemia （OR = 5.559, 95% CI 1.053 -29.347, P = 0.043）. Compared with the patients with mild pemphigus, the prevalence rate of infections significantly increased in the patients with moderate （OR = 4.676, 95% CI 1.276 - 17.123, P < 0.05） or severe pemphigus （OR = 16.529, 95% CI 4.183 - 65.314, P < 0.001）. The prevalence of infections in patients with pemphigus was unaffected by gender, types of pemphigus, or the presence of hypertension or diabetes （all P > 0.05）. Among the 145 patients who were followed up, 33 were completely cured, 67 were cured clinically, 23 received improvement, 10 experienced relapse or exacerbation, and 12 died. Of the 12 dead patients, 3 died of pneumonia, 2 died of exacerbated pemphigus and skin infections, and 1 died of sepsis. Conclusions High disease severity and hypoproteinemia are risk factors for infections in patients with pemphigus. Bacterial infection is a common complication in patients with pemphigus, and severe infections are one of the causes of death in patients with pemphigus.

Key words: Pemphigus, Infection, Staphylococcus aureus, Hypoproteinemia, Prognosis