Anosmia FAQ

Anosmia – loss of the sense of smell – can occur for several different reasons. Each affects a different part of the olfactory system. Some common causes of anosmia include:

• Chronic nasal-sinus disease, e.g., rhinitis (inflammation in the nose caused by viral, bacterial or fungal infections), nasal polyps and/or chronic sinus infections – can block the passage of odor molecules to the smell receptors or interfere with how the receptors detect odors.
• Viral respiratory infections (common colds) – can damage or destroy the smell receptor cells.
• Head injury – can sever the olfactory nerve fibers that send smell information to the brain and/or damage parts of the brain that process smell information
• Aging — repeated exposure of the olfactory receptors to environmental air-borne toxins can damage the smell receptors and/or the receptor cells can lose the ability to regenerate
• Congenital or in-born causes – the reasons for this are unknown at this time.

The only established treatments for anosmia are in cases of chronic nasal-sinus disease (see above). Therefore, it is important that you consult with an otolaryngologist (ear, nose and throat specialist) to determine if this may be the source of your anosmia. If so, possible treatment options might include:

• antibiotics
• topical or oral corticosteroids to reduce the inflammation, or
• surgery to remove inflamed tissue and/or nasal polyps.

Smell-training (twice daily exposure to several intense odors) may improve the sense of smell in some – but not all – people whose anosmia is due to viral infection, head trauma or aging. However, it is not yet known whether this is a long-term solution. The website http://www.smelltraining.co.uk contains extensive information about smell training.

No other treatments for anosmia have been confirmed using randomized double-blind trials, the gold standard that medical scientists use to establish a potential treatment’s effectiveness.

Taste is detected by receptors on the tongue that sense sweet, sour, salty, bitter and savory/umami. Many people with anosmia believe that they also have lost their sense of taste. However, unlike smell, the sense of taste is very resistant to damage, and what actually is lost is the ability to sense flavor.

This is because the distinctive flavors of most foods and drinks comes more from smell than it does from taste. Sugar has a taste (sweet), but strawberry, banana, or licorice flavors are actually smells. An airway between the nose and mouth lets healthy people combine aroma with the five basic tastes to enjoy thousands of flavors. However, people with anosmia cannot detect the crucial olfactory component of flavor.

You can test your sense of taste by dissolving sugar and salt in your mouth, sipping vinegar, and seeing if you can taste the bitterness of black coffee on your tongue (even if you can no longer perceive its aroma and full flavor).

Individuals with anosmia can appreciate foods through their sense of taste, their perception of textural differences, and their ability to detect chili burn, menthol cooling, pepper tingling and other sensations using a separate sensory system that detects ‘feel’ (see below).

A separate sensory system in the nose, eyes and skin detects sensations of irritation, heat, pain and coolness. For example, cut onions release airborne molecules that make your eyes water. This system is unrelated to smell, but many odor molecules can also stimulate this system, especially at high concentrations. This system most likely accounts for your response to some “smells,” including ginger, cinnamon, and mint.

There is no evidence that unexplained smell loss (eg, not caused by congenital factors or head trauma or upper respiratory viruses or chronic rhinosinusitis) will increase risk for neurological diseases such as Alzheimer’s or Parkinson’s, or that it is even necessarily a sign of these diseases in the absence of other symptoms.

If you notice a problem with your sense of smell, you should first consult an otolaryngologist (ear, nose and throat specialist), preferably one who sub-specializes in nasal-sinus disease (as opposed to head-neck cancer or auditory problems). In cases of smell loss following a head injury, you may also want to consult a neurologist who specializes in traumatic brain injury.

Because anosmia is an invisible disability, it often is not detected in children until they are school-aged and begin themselves to notice that others are describing sensations that they cannot relate to. You first should seek advice from an otolaryngologist (ear, nose and throat specialist) to determine if nasal inflammation or blockage may be causing the problem.

If your child’s smell loss cannot be explained and s/he is pre-pubertal or experiencing delayed puberty, you should request an endocrinological evaluation. Smell loss in children can sometimes be a symptom of Kallmann’s Syndrome, a rare genetic disorder also characterized by delayed puberty. Many symptoms of Kallmann’s (although not the smell loss) can be addressed with hormone therapy.

The sense of smell serves as a warning system, and anosmic individuals are unable to detect environmental dangers such as gas leaks, smoke from fire, or the rancid scent of spoiled food. The ability to prepare and enjoy food, an important family and social activity, also is reduced, as smell is a big part of food flavor. Anosmics also miss emotional connections associated with smell and cannot enjoy the pleasurable aspects of smell, from the scent of lilacs in the spring to the smell of babies’ heads. Many individuals, especially those with acquired anosmia, report symptoms of depression, anxiety, and isolation, and describe the condition as like experiencing the world through a frosted window. Some also experience highly unpleasant and distressing phantom smells.

Several factors contribute to a general lack of knowledge about anosmia

• Our knowledge of the sense of smell lags behind other senses such as vision and hearing. This limits our ability to understand what happens when things go wrong and thus to develop effective treatments.
• Anosmia is an invisible and underappreciated disability. Many people take the sense of smell for granted and only realize how important it actually is after it is gone. Thus it is difficult for physicians to understand the debilitating impact of anosmia.
• Many cases of anosmia are related to damage to the smell receptor cells, which also are nerve cells. Unfortunately, modern medicine still has limited ability to treat nerve damage anywhere in the body.

Inherited congenital anosmia appears to be very rare, with a number of different subtypes that will each be passed down with different frequencies.

If you do have inherited congenital anosmia, we cannot predict the likelihood of your children also being anosmic without knowing the genetic cause of your particular subtype of anosmia.

There is no evidence that anosmia is in any way related to the ability to have children. Like other parents with disabilities, anosmic parents will need to make certain accommodations with respect to child-rearing, but smell loss will not prevent individuals with anosmia from raising happy, healthy and loving children.

Anosmia has long endured the dual challenge of being an invisible disability that involves our least-understood sensory system: smell. In the past few years, however, there has been a surge of interest about anosmia, with groups such as the Monell Center in the US and Fifth Sense in the UK working to raise awareness about the incidence and consequences of anosmia. Anosmia sufferers throughout the world are connecting through groups on Facebook and Yahoo to share their experiences and information, giving a voice to this invisible disability. And, targeted research at Monell, made possible through government grants and contributions from individuals, is focusing on understanding the underlying causes of anosmia to identify potential treatments. The path may be a long one, but now there is a sense of hope.

See the website http://www.anosmiaawareness.org for additional information and resources for individuals with smell loss.

Information in this FAQ is for educational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. You should also ask your physician or other healthcare provider to assist you in interpreting the above information and in applying the information to your individual case.