Dysosmia is a neurological disorder that causes an altered sense of smell. Dysosmia can be classified as either parosmia (also called troposmia) or phantosmia. Clinically, olfaction can fail in any of three ways: (i) decreased sensitivity (hyposmia, anosmia) and two types of distortion (dysosmia); (ii) distorted quality of an odorant stimulation (troposmia); (iii) perceived odor when no odorant is present (phantosmia, hallucination).While vitamin or mineral deficiencies can cause altered smell, this would be very unlikely unless you are on a very restricted diet or have an intestinal problem that impairs absorption of nutrients.