Phantosmia. Might lead to accidents.

Hello, my mom is suffering with with continuous bad odour(like sap of leaves) since 3 months.Because of this she is unable sense any other smells.Shez smelling only that particular odour.Its being dangerous quite sometime.Now she is getting that smell even in mouth by spoiling taste of food leading to loss of appetite,nausea.we consulted many doctors but no one could help her with proper treatment.It has been quite shocking for them as a rare situation.CT scan,lung scanning,nose scan all the reports were normal.Doctors advised her to leave and to bother about this.But my mom is feeling very stressed due to loss of all good smells.This bad or particular odour makes her irritate,agony.She was exposed to extreme cold breeze in december in TIRUMALA where number of trees present,doctors said this might be one of the reasons.Please help with a solution of proper treatment and suggest me to whom should I consult.It is known that loss of olfaction might lead to accidents.