In the fight against the COVID-19 epidemic that is currently a major global public health issue, social distancing has been imposed to prevent the massive transmission, thus doctors in hospitals have turned to telemedicine in order to be able to monitor their patient notably those suffering from chronic diseases. To do so, patients need to share their physiological data with doctors. In order to share this data safely, prevent malicious users from tampering with it and protect the privacy of patients, access control becomes a fundamental requirement. In order to set up a real-time (Internet of Thing) IoT enabled healthcare system (HS) scenario like telemedicine, Fog computing (FC) seems to be the best solution comparing to Cloud computing since it provides low latency, highly mobile and geo-distributed services and temporary storage. In this paper, the focus is on access control in the telemedicine systems. Our proposal is based, on one hand, the concept of Fog computing to ensure the distributed aspect needed in the monitoring of patient health remotely; and on the other hand Blockchain (BC) smart contracts, in order to provide a dynamic, optimized and self-adjusted access control.