New-Onset Insulin Allergy After COVID-19 Infection in an Insulin-Dependent Type-2 Diabetic Patient: A Rare Complication

Coronavirus disease 2019 (COVID-19) is an infectious respiratory disease caused by the novel coronavirus severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Initially, it was reported in December 2019 and became a global pandemic in March 2020, with many presentations and after-effects. We report the case of a 68-year-old female patient who presented to the emergency room with the chief complaint of a skin rash and itching all over her body, developing within a few minutes of insulin injection. The patient had tested positive for COVID-19 almost eight days ago and was self-quarantined. She was a known diabetic for the past 28 years. Her blood glucose levels were maintained within the normal range by a combination regimen of oral anti-diabetic drugs and subcutaneous humulin 70/30 (70% neutral protamine Hagedorn (NPH) insulin and 30% regular human insulin) injections. After careful examination and thorough history taking, a newly acquired insulin allergy was diagnosed in the patient, attributed to her disrupted immune system due to the recent COVID-19 infection.