Anosmia means loss of the sense of smell; it could be temporarily or permanently, and usually develops due to medical issues related to the nose such as nasal congestion, flu, allergic rhinitis. On the other side, there are several reasons many people don't know that could lead to anosmia. So we will highlight the uncommon causes for anosmia.

1. Pregnancy: hormonal changes related to pregnancy leads to a different perception of smells (foods, perfumes… etc.), also these hormonal changes could be responsible for temporary anosmia. The sense of smell is restored after few days of delivery.
2. Diabetes: long-term uncontrolled hyperglycemia causes reversible or irreversible damage of the olfactory nerve, which leads to temporary or permanent anosmia.
3. Direct head trauma: head trauma may result in damage of the olfactory center in the brain, leading to permanent anosmia.
4. Advanced or invasive gingivitis: gum inflammation in the upper jaw could extend to nerve endings of the olfactory nerve, leading to gradual loss of sense of smell.
5. Medication: administration of certain antihypertensive drugs (such as Ramipril or Ezapril) could involve some side effects which include anosmia.
6. Aging: gradual loss of sense of smell could happen as a physiological process related to aging.
7. Chemicals: long-term exposure to highly-concentrated chemicals such as bleaches could lead to anosmia.