How do throat lozenges work? They lubricate the throat, suppressing the irritation.
Why do we get sore throats? The most common cause of sore throats is viral infections. The second most common is a bacterial infection. The common cold is a good example of a viral infection and strep throat is a good example of a bacterial infection.
With the common cold you get infected with a virus, by direct physical contact with an infected person or touching a surface contaminated with the virus. We touch our faces hundreds of times a day, so it is very easy to transport that virus into our mouth or nose. Once inside the body, the rhinovirus attaches to the lining of the nose and throat. It settles in and starts to replicate.
It takes about two days for the virus to replicate enough for the immune system to detect it. Once it has, the immune system goes to work. Your blood vessels swell to make more space for white blood cells to get to the infected area. The swollen blood vessels can press on the nasal passage, causing a blocked nose.
White blood cells are created in the bone marrow and in the lymph nodes. The white blood cells from the bone marrow travel in the blood and the white blood cells from the lymph nodes travel through the lymph fluid. The lymph fluid flows along a network of lymph vessels, with 600 lymph nodes around the body working as junctions. The lymph fluid carries viruses that have infected the body to the lymph nodes where the white blood cells kills them. Once they are killed, they get passed out of the lymph nodes into the blood stream, where they are carried away to the kidneys. The lymph nodes often swell up when we are fighting an infection because they are full of fluid and white blood cells.
When you have an infection in the nose and throat, one of the body’s reactions is to produce mucus. It produces far more mucus than can be dealt with and some of it runs out of the nose, causing a runny nose. The rest of it runs down the throat and into the lungs, which causes us to cough. The body’s idea is that coughing might get out the irritant. The trouble is, coughing irritates the lungs and the throat more, which starts a vicious cycle.
So, where does the sore throat come from? The infected area at the back of the throat and the surrounding area, called the pharynx, gets inflamed. When bacteria or virus lodge in the throat, the immune system sends out inflammatory cells. Their job is to trap the viruses and the bacteria and to start healing the injured tissue. This causes the tissue to swell, and the inflammatory cells also activate the pain receptors. The pain that comes with a sore throat is actually the sign that your body is trying to fix itself.
So, how do throat lozenges work? There is no way to kill the viruses or bacteria other than to let the body sort it out. The throat lozenges are meant to ease the symptoms and not fight the cause. The lozenge usually has a mixture of medicines and oils inside a hard sugar shell. When you suck it, the sugar coating dissolves and releases the contents down the throat.
One of the common medicines is benzocaine. It is a common local anesthetic and will numb the areas of the throat that it comes into contact with. Benzocaine can inhibit the pain receptors that the inflammatory cells are acting upon. It is only a short term reaction, which is why you have to use more lozenges.
They probably contain menthol. which can work on nasal and chest congestion. It can trigger the sensors in the throat that react to cold, making the brain think the burning feeling of the inflammation has gone away. When it triggers the receptors in the nose, the brain thinks that cold air is passing, so we think we are breathing more easily, even though we probably aren’t. They may contain eucalyptus oil, which has the same reaction as menthol.
Many of them may also contain a chemical pain killer. This can reduce some of the swelling, but it is also only temporary.
So, all of the ingredients in a throat lozenge desensitize the pain receptors in the throat that have been activated by the immune system’s inflammatory response. They can also trick us into thinking that we are breathing more easily. However, the sore throat is part of the body’s efforts to cure us, so we shouldn’t be too upset, no matter how painful it is. And this is what I learned today.
Sources
https://my.clevelandclinic.org/health/symptoms/21660-inflammation
https://my.clevelandclinic.org/health/diseases/15219-swollen-lymph-nodes
https://www.ncbi.nlm.nih.gov/books/NBK519550/
https://my.clevelandclinic.org/health/body/21871-white-blood-cells
https://en.wikipedia.org/wiki/Pharyngitis