Allergy is a potential outcome of dysregulated immune system. Previous studies have shown the association of allergy and autoimmune diseases, however, there is few study to investigate the relationship between allergy and anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis. Thus, we investigate the rate of allergy in patients with anti-NMDAR encephalitis and analyze the risk factors.The rate of allergy was investigated in patients with anti-NMDAR encephalitis and was compared with patients with virus encephalitis. The clinical cutaneous characters were described in details. All patients with anti-NMDAR encephalitis were divided into allergic and nonallergic group. Clinical factors were compared in the two groups, and logistic regression model was also used to analyze possible risk factors of allergy.Patients with anti-NMDAR encephalitis had a higher rate of allergy than those with viral encephalitis (22.1% vs 9.2%, odds ratio (OR)=3.23, confidence interval (CI)=1.40-7.42, P=0.006). In patients with anti-NMDAR encephalitis, allergic patients exhibited longer days in hospital (30days vs 22days, P=0.005) and higher occurrence of decreased consciousness (81.5% vs 58.9%, P=0.031), higher rate of complications (77.8% vs 57.9%, P=0.046) and abnormal electroencephalography (EEG) (100% vs 78.6%, P=0.021) than patients without allergy. Cerebrospinal fluid (CSF) antibody titers of allergic patients during the disease course were also higher than nonallergic patients (P=0.004). However, further logistic regression analysis did not reveal independent predictors of allergy.Patients with anti-NMDAR encephalitis show higher allergic rate than those with virus encephalitis. Patients with allergy show higher CSF antibody titers and greater illness severity. However, the final outcome of anti-NMDAR encephalitis was not influenced.