Differential Diagnosis for Sudden Anosmia on Day 3 of a Cold with Negative Covid Swab
- Single Most Likely Diagnosis
- Viral rhinitis or common cold: The sudden onset of anosmia (loss of smell) on the third day of a cold is consistent with a viral upper respiratory infection, which can cause inflammation and swelling in the nasal passages, leading to a temporary loss of smell.
- Other Likely Diagnoses
- Sinusitis: An infection or inflammation of the sinuses can cause a loss of smell, and it often occurs in conjunction with a cold.
- Allergic rhinitis: Seasonal or environmental allergies can lead to nasal congestion and a loss of smell.
- Nasal polyps: Growths in the nasal passages can obstruct the sense of smell.
- Do Not Miss Diagnoses
- Meningitis: Although rare, meningitis is a potentially life-threatening condition that can cause a sudden loss of smell, among other symptoms like headache, fever, and stiff neck.
- Intracranial tumor: A tumor in the brain, particularly in the area responsible for processing smells, can cause a loss of smell.
- Vasculitis (e.g., giant cell arteritis): Inflammation of the blood vessels can lead to a loss of smell and other symptoms like headache and visual disturbances.
- Rare Diagnoses
- Kallmann syndrome: A rare genetic disorder characterized by a loss of smell and delayed or absent puberty.
- Parkinson's disease: A neurodegenerative disorder that can cause a loss of smell, often as an early symptom.
- Traumatic brain injury: A head injury can damage the nerves responsible for smell, leading to anosmia.
- Exposure to toxic substances: Certain chemicals can damage the olfactory system, causing a loss of smell.