Elderly mother

My mother is currently taking candersartan for high blood pressure.She has been on it for approximately 5months. Just recently she is plagued by headaches and has recently complained of being nasally congested. However, her eyes have become very puffy and swollen.Could this be an allergic reactiojn to the tablet. The doctor has seen her and we did mention the eyes and headache but i am sure it is very difficult to assess whether it is the tablets that are responsible.She is also taking iron tablets and alpurinol.

Thankyou for your help