Parosmia is:

(a) Perversion of smell sensation(Ref. Cummings, 6th ed., 639)Parosmia is perversion of smell sensation. Here good smell appears bad to the patient.Absolute loss of smell sensation is called anosmia.Decreased smell sensation is called hyposmia. Normal age related decline in smell sensation is presbyosmia.Phantosmia is the perception of a smell in the absence of any physical odours. The odour can range from pleasant to disgusting smells.Cacosmia or an unpleasant phantosmia is the perception of a bad smell without an odorant stimulus.