A technology computer-aided design (TCAD) simulation framework of gas desorption induced by self-heating in carbon nanotube (CNT) field effect transistor (FET) gas sensors is presented. Its key feature is the use of temperature profiles extracted from electrothermal simulations to determine the change of the effective gas-induced doping concentration during the gas desorption phase. The approach allows to investigate the impact of geometrical and physical parameters, in particular the ones related to contacts, on the self-heating desorption process. The main conclusion is that, due to the nonuniform self-heating temperature profile, the near-threshold part of the IDS-VGS curves recover their pristine aspect faster than the rest of the characteristics.