LAUSR

Dear Editor, Atopic dermatitis is a chronic skin disease characterized by abnormalities in the skin barrier, inflammatory immune response, and pruritus and increases the risk of skin infection [1]. Exit site infections can progress to peritonitis in peritoneal dialysis (PD) patients, requiring removal of the cause and early treatment. The relationship between skin diseases such as atopic dermatitis and exit site infection is unclear. Some reports showed that dupilumab is useful for severe atopic dermatitis, but there is a lack of knowledge on PD patients. Here we report a successful response to dupilumab in a patient with recurrent exit site and tunnel infections due to atopic dermatitis. A 39-year-old Japanese male with end-stage renal failure caused by Alport syndrome underwent PD for 7 years. He had suffered from atopic dermatitis since his childhood. His skin was very dry and itchy, which was not well controlled by moisturizers, topical corticosteroids, and antihistamines. A total of 27 exit site and tunnel infections occurred in 7 years until dupilumab was introduced in 2019. Then, dupilumab controlled his itchy well and enabled him to stop tropical corticosteroids and antihistamines. Serum IgE level dropped from 2561 to 593 IU/ml. Significant tunnel infection never occurred almost for 1 year thereafter. This is the first report that treatment of atopic dermatitis can decrease the incidence of exit site and tunnel infections. A limited number of studies have reported on PD patients with atopic dermatitis. One showed a case of spreading infective endocarditis [2], and another showed a case of repeated peritonitis [3]. Dupilumab is a fully human monoclonal antibody that binds to the subunit of the interleukin (IL) 4 receptor and inhibits signaling of IL-4 and IL-13, cytokines of type 2 helper T lymphocytes which plays a key role in atopic dermatitis. It is indicated for severe atopic dermatitis not adequately controlled to topical prescription therapies. It is reported that dupilumab is associated with a decreased incidence of skin infections in atopic dermatitis [4]. Dupilumab is not renal excretion and has few serious adverse events compared with conventional immunosuppressive agents, so it could be used safely and long-term in PD patients. In conclusion, we have experienced a case of a PD patient whose recurrent exit site and tunnel infections were controlled by the use of dupilumab.