Central to many of the new developments is an improved understanding of why odorants - molecules we detect as smell - are not being detected. Doctors used to think the problem was because of an obstruction preventing the odorants from being physically able to reach the sensory neurons. This was most common in cases of patients with polyps.
However, even after polyps were successfully removed, doctors noticed that only one in four people regained their sense of smell. They proposed that inflammation in the nose could be the problem. Since they started looking at how to manage inflammation, new ideas for treatment to restore the sense of smell have begun to be considered.
Steroids are often prescribed to help manage inflammation, but their effectiveness is short lived and the side-effects make it inadvisable to use for longer periods of time. Steroid irrigations, which are better tolerated, can be a more effective way to reach inflammation.
A new generation of treatment - biologics - has much more potential to deliver long-lasting recovery. Although there is more research to do, studies are indicating that drugs like dupilizumab can restore the sense of smell. This type of therapy uses monoclonal antibodies to block the chemical processes that cause inflammation. It’s an exciting area of development, but several more years of research are needed to fully understand the role of biologics in treatment and becoming a widely available therapy.
Platelet-rich plasma (PRP) injections are attracting a lot of interest among doctors. The treatment uses a patient’s own blood cells to accelerate healing in a specific area and has been demonstrated to be effective for a variety of conditions, such as sports injuries. This type of therapy has anti-inflammatory and repair properties that could support the healing process.
Antihistamine is another therapy for managing inflammation in the body that could potentially address the issue preventing odorant reaching the olfactory sensory neurons. More research needs to be done to determine dose levels and effectiveness, but it’s a promising area for exploration.
Although there is little evidence for the effectiveness of alpha lipoic acid, vitamin A and Omega3 in the recovery of smell, it is likely that these also have anti-inflammatory properties which is why we see continued anecdotal reports of their use supporting the healing process.
Many new potential treatments are not evidenced. It is vital that randomised control trials are properly conducted to truly compare the effect. In the worst cases, the treatment can actually be worse for the patient as was found in the use of zinc paste in the nose. Randomised control trials take time, and of course, money. Just writing the proposal and seeking funding for a trial can take two years. The full journey from idea to being accepted as a therapy will be around five years - and that’s if the treatment is demonstrated to be effective. Read more about patient involvement to find new treatments.
Another issue is the affordability. In the UK new treatments have to be approved by NICE before they can be used on the NHS, and their cost versus benefit is an important factor in gaining approval. Biologics, for example, may prove to be effective but it’s currently a very expensive therapy and it’s unlikely it will be made available on the NHS in the near future.
Although readily available and effective treatments are still some way off, there is good reason to hold on to hope for recovery. One of the unknowns is whether a person will lose their ability to smell after a long period of time has passed. Some doctors suggest that the olfactory system becomes so weak without use it can stop functioning altogether. This has led to reports of people being told they are unlikely to smell again after just a year.
However, the research is showing that this just isn’t the case, and recovery after long-term smell loss is perfectly possible. Professor Hopkins described the experience of one patient who, after 10 years without being able to smell, found a full range of smell returning just days after treatment with biologics. Watch our webinar on 'long-term recovery stories'.
Every researcher that gives their time to keeping us informed shares the same message: don’t give up hope, there is every reason to look forward to finding a renewed enjoyment of a life with smell.
April 25, 2022