Q. Thanks for agreeing to speak with us, Simon. Can you tell us about yourself?
A. I’m a consultant Rhinologist (Nose Specialist) at the Royal National Throat, Nose and Ear Hospital in London. I studied Medicine at the University of Cape Town and trained in ENT surgery in the North London region. I have a research interest in smell and sinus disorders as well as the genetic disease hereditary haemorrhagic telangiectasia and am pursuing a PhD examining a strange theory of the function of the olfactory receptor called the vibrational hypothesis. Although we have always seen patients with olfactory disorders at the RNTNEH, we are in the process of piloting a specialist smell clinic at the RNTNEH, which is something we’ve had very positive feedback on at the moment.
Q. We are grateful that you'd agreed to share information with the Facebook group. The topic I have for you is steroid use for patients with smell loss. Can you explain why this treatment is used, and how the steroids are meant to be helpful? Which kinds of smell loss would be treated with steroids?
A. Everyone has lost their sense of smell when they have a cold with a blocked nose. This is the commonest smell loss: obstructive, where the underlying olfactory system is intact but the odour molecules can’t get to the lining at the top of the nose, between the eyes, where the smell nerves are. This obstruction can be due to bony or cartilagenous abnormalities, but usually it’s because there is inflammation of the lining of the nose. Inflammation is the body’s response to injury, where water and a specific group of cells are mobilised into the area of the injury, be it to fight a viral attack or repair a cut. Classically it is marked by swelling, redness, warmth and pain or itchiness. You can imagine the results of this process in a small bony box with lots of soft tissue and a very rich blood supply, which is what the nose is. Steroids are very effective at reducing inflammation. Since obstruction is the commonest cause of smell loss, giving a short course of a very powerful shrinking agent is a sensible approach to start with. I use the steroids as a way of seeing whether there is still a normal sense of smell and whether opening the nose up in some way would restore it.
Q. How does the use of steroid tablets differ from that of steroid nasal sprays?
A. Steroid tablets are systemic. They’re taken by mouth, absorbed into the body by the gut and spread around the body through the bloodstream, so they don’t only act on the inflamed tissue in the nose, but everywhere in the body. The chances of side effects are therefore much greater, and the dangers of long term steroids on the body are well known. Topical steroids (drops or sprays) only act where they land, once they pass into the gut they are broken down. Only a small percentage of the dose makes it into the body. Biopsy studies have shown that inflamed noses look normal under the microscope when they are treated with sprays, compared to untreated noses.
Q. Do steroids have side effects? How do you advise patients about managing any side effects and the trade off with possible improvement? Do you think that patients who decide against taking oral steroids might be causing damage to their sense of smell down the line? In other words, is there ever a therapeutic effect to steroids, or do they merely reduce symptoms?
A. I don’t think that there is a difference between managing symptoms and having a therapeutic effect. For people with an obstructive cause for their smell loss, who get better with steroids, there is no reason not to take the nasal sprays or drops. There is some suggestion that if you lose your sense of smell through obstruction for a long time, then it does atrophy, but I think the evidence for this is weak. At the moment, steroids are all we have for unblocking an inflamed nose, although there are promising new therapies in the pipeline.
Q. What types of smell loss are there?
A. I think of smell loss as having two broad categories: obstructive, where the underlying machinery of smell is functional but the smelly molecules can’t get to it; and neural, where the “machinery” is not working in some way. We still have a long way to go in understanding the machinery of smell, and the causes of some obstruction, but it's a useful categorisation.
Thank you, Simon!