Merciful anosmia is seen in:
In atrophic rhinitis, there is foul smell from the nose, making the patient a social outcast though the patient himself is unaware of the smell due to marked anosmia which accompanies the degenerative changes. This is called as merciful anosmia.
Atrophic rhinitis
Allergic rhinitis
Ethmoidal polyposis
Wegener's granulomatosis