Case of subcutaneous insulin resistance syndrome treated with ultra‐rapid insulin lispro

Subcutaneous insulin resistance syndrome is a rare condition that causes difficulty in glycemic control due to severe resistance to subcutaneous insulin injections. We herein present a case of a 40‐year‐old woman with type 2 diabetes mellitus who had been diagnosed with subcutaneous insulin resistance syndrome since the age of 29 years, and had been persistently treated with continuous subcutaneous insulin infusion using a mixture of insulin lispro and heparin. The patient was switched from insulin lispro plus heparin to ultra‐rapid insulin lispro; given that it contains treprostinil and citrate, it is expected to have similar effects as heparin, and shows similar glucose‐lowering effects and insulin absorption. Our results suggest that treatment with ultra‐rapid insulin lispro is effective for subcutaneous insulin resistance syndrome. We reported a case of subcutaneous insulin resistance syndrome that achieved good glycemic control with ultra‐rapid insulin lispro, novel insulin formulation. Although it has been reported that the combination of insulin lispro and heparin is effective for subcutaneous insulin resistance syndrome, it is suggested that ultra‐rapid insulin lispro might provide good glycemic control without heparin.