Smell Disorders

Smell disorders can seriously impact a person's life. The four different smell disorders are hyposmia, anosmia, parosmia, and phantosmia. Hyposmia is the reduced ability to smell, anosmia is when someone is born with the sense of smell, parosmia is when there is a change to the normal perception of odors and phantosmia is when someone smells something that is not there. Any kind of loss of smell can occur from aging, smoking, nasal infections, hormonal disturbances, or even certain chemicals. Smell disorders are treated by a ENT doctor and surgery is sometimes used for people to obtain their sense of smell back.

http://www.nidcd.nih.gov/health/smelltaste/pages/smell.aspx#3