CAUSES OF ANOSMIA

• Head Injury:

  • severe blows to the head

  • concussion or minor head trauma

  • damage to the olfactory nerve, which contains smell receptors

  • damage to the olfactory bulbs

  • shearing or stretching of the olfactory nerves at the cribiform plate, which occurs in approximately 10 % of major head injuries

  • occasionally associated with a fracture running through the nose and the cribiform plate

• Surgery

  • cranial surgery

  • surgery with general anesthesia

  • transphenodial surgery

• Sinus problems

  • sinus cauterization can damage the olfactory receptors

  • severe or chronic sinus infection can damage the olfactory nerves

  • long-term use of nasal spray to deal with sinus problems

  • infection of the nasal sinuses

• Illness

  • violent coughing can damage the nerves in the olfactory glands

  • a viral infection or respiratory virus may damage the olfactory nerve. When a viral infection like the "flu" involves the cells of the olfactory epithelium, the viral particles destroy the normal functioning of the nasal olfactory cells.

  • allergy or infection in the nasal cavity

  • Anosmia can occur transiently in many nasal disorders, including sinusitis and nasal blockage from any cause, but when protracted may warrant a workup.

• Born without a sense of smell (congenital):

  • perhaps due to a problem in a fetus’ pre-natal development, resulting in the olfactory nerves never developing

  • can be transmitted genetically

• Inflammatory conditions (swelling):

  • severe inflamation of the nasal passages causing nasal obstruction

  • due to allergy or infection, either by viruses such as the common cold or bacteria as often found in sinusitis

  • swelling of the brain (due to an accident, etc.)

  • concussion

• Structural causes:

  • deviated nasal septum

  • crooked nose

  • can physically impede air flow through the nose

  • nasal obstruction or any impairment of breathing: prevents air from circulating over the olfactory epithelium, so that odors are not available to the olfactory epithelium and are not detected

• Polyps or Tumors:

  • benign, such as nasal polyps. For example, nasal polyps associated with allergic rhinitis.

  • malignant, such as an epidermoid carcinoma

  • pituitary tumor

• Dentistry work

  • dental injections

  • damage to both olfaction and taste

  • injury to the taste buds

  • injury to the nerves responsible for taste

  • dental work can set a small electric charge in the mouth, which may be perceived as an abnormal taste or a stinging feeling.

  • poor dental hygiene may cause distortions of taste.

• Medical conditions:

  • Kallmann's Syndrome: a genetically determined syndrome. Those affected fail to develop olfactory bulbs (and thus are anosmic) as a result of failure of olfactory nerves to make contact with the developing brain early in life. Kallmann's most often affects males.

  • psychological or psychiatric conditions can affect smell perception: for example, depression, hysteric conversion reactions, and schizophrenia.

  • Opitz-Frias Syndrome: a very rare problem with cranio-facial development

  • with age there can be some diminution in the sense of smell, as with vision.

  • spinal meningitis during infance

  • Uncinate epilepsy can produce brief, vivid, unpleasant olfactory hallucinations

  • Sjögren's syndrome

• Medication (see below for more):

  • long-term use of nasal spray to deal with sinus problems.

  • antibiotics such as metronidazole and cefuroxime and cipro

  • zythromax

  • radiation therapy of the head and neck

  • desquamation of the tongue can impair taste

  • various drugs such as amitriptyline and vincristine can alter taste

  • ACE inhibitors:

    • Vasotec I.V.: Please see page 7 of: http://www.fda.gov/cder/foi/label/2001/19309s23lbl.pdf

    • quinapril hydrochlorid

  • Nasal sprays to cure common cold symptoms, especially those including zinc. Anosmics have reported losing their sense of smell after using such products as Cold-eeze and Zicam. (Please note that the Anosmia Foundation will not answer any questions about this product.) Please click here for more information about Intranasal Zinc.
    For information about the lawsuit against Matrixx Initiatives, Inc., the producers of Zicam, please click here.  
    For a statement from Matrixx Inc., please click here.

  • amikacin therapy, the use of intravenous amikacin sulfate (generally this anosmia is reversible)
  • antibiotic therapy
  • the use of doxycycline, amoxicillin, clarithromycin, roxithromycin, kanamycin sulfate, and streptomycin sulfate

• Chemicals:

  • Chemical burns may damage the olfactory epithelium.

  • cleaning agents with a basic pH such as ammonium.

• Irritants:

  • cigarette smoke can interfere with one's ability to smell.

  • drying of the oral mucosa from heavy smoking can affect taste

  • Irritants such as cigarette smoke, air pollutants, and chemical odors also may contribute to the perpetuation of the symptoms of anosmia.