Modern Theory: Asthma Is An Abnormal Immune Response

Asthma was once considered a nervous disorder. The person who gave credibility to this theory was Dr. Henry Hyde Salter. He wrote a series of articles beginning in 1850 on what he knew about asthma. The articles were later published in a book called "On Asthma: It's Pathology And Treatment."

Dr. Salter knew that asthma was a real physiological disease. However, he believed the cause was psychosomatic. He believed there were nerves from the brain to the lungs. And I'm greatly exaggerating his theory. But, strong emotions triggers the brain to send impulses down these nerves to the bronchial airways to trigger asthma episodes.

It's easy to understand the confusion. Just think of it like this: for 99.9% of our history of medicine physicians were not aware of an immune system. The immune system wasn't defined until after the turn of the 20th century. And even then it took a long time to study it and to get to the point we know what we know today.

And genetic research is still in its infancy. We were just at the dawn of genetic research when I was in high school. I remember learning about the nature of DNA at that time. Now we know so much more about DNA. That it holds your genes. And that every cell in your body has your entire gene code.

Today, researchers know every gene. They know what most genes do. They have decoded the entire gene code. And so now efforts are on to learn the link between genes and the various diseases that plague mankind. One example of this are efforts to learn all of the potential genes for causing asthma.

They have now discovered over 100 asthma genes. And, like the nervous system and your immune system, they cannot be seen with the naked eye. So, Dr. Salter was left to using his imagination to explain the underlying cause of asthma. So, in his mind it was a nervous disorder to be treated with medicines to soothe the mind.

And this theory made sense in a way. Asthmatics tended to have a nervous tendency. They spent lots of time with their mothers. This was mainly because they were unable to work on the farm and do guy jobs. It was because of their asthma, not the other way around. Dr. Salter thought asthma caused men to hang out with their mothers more. So, he devised a theory that asthma was a desire or a calling out to the mother. It was a yearning for the mother.

It's very interesting. I think the best person to describe Dr. Salter's theories was David McCullough in his book, "Mornings On Horseback." The chapter that he talks about Teddy Roosevelt's struggles with asthma is chapter 2. It's a great read for anyone interested. And it's important for any asthma historian to read. It explains the thinking of most asthma doctors during the second half of the 19th century.

This is important because Dr. Salter's book was the most popular book on asthma among the medical community. Dr. Salter's theories and treatments for asthma gained much credibility. They were often sited by other physicians.

Around 1900 some new discoveries were made. A significant one was made when the adrenal gland was being studied. Researchers were racing to isolate all the hormones inside of it, particularly epinephrine. It was discovered in 1901 by a Japanese scientist. It was known right away to be a strong vasoconstrictor.

Many experiments were done using epinephrine. You can only imagine the excitement. What diseases will benefit from this. And one disease experimented on with this new medicine was asthma. So, it was soon learned that epinephrine (often referred to as adrenaline) could quickly end asthma attacks. A theory was devised that it ended asthma by causing vasoconstriction. This slowed the flow of blood to the lungs, which opened airways.

A common theory at this time was that asthma was caused by congested lungs. Today we would refer to this as heart failure. But, back then they had a hard time differentiating between the different causes of shortness of breath. So, if you presented with shortness of breath you were almost always diagnosed with asthma.

This theory was prevalent for a while. But, eventually it was learned that epinephrine was also a powerful bronchodilator. It ended asthma attacks by telling bronchial smooth muscles to calm down. It relaxed bronchial smooth muscles. And this brought back the other theory of Dr. Salters that asthma is a disease of bronchospasm.

Still, by the 1930s the nervous theory was brought back to life. One doctor from this era listed asthma as one of the seven psychosomatic disorders. Asthma was all in your head. And so the treatment was medicines to soothe the mind. And this theory was so prevalent that it almost single handily gave birth the the asthma hospital craze of the 1930s to the 1990s.

So, I could go on about these theories. I could go on about asthma hospitals. I have already on my "Asthma History" blog. But here I wanted to explain why the nervous theory of asthma was not so bad. Medicines to sooth the mind were very helpful for asthma, especially when there were not truly effective asthma medicines prior to the discovery of epinephrine.

Sure, we think of asthma cigarettes as terrible for asthma. We now know that smoking can damage lungs. But, back in the day, that knowledge was not there. Plus, inhaling smoke for most of history was the only way to inhale respiratory medicine. So, it was normal to roll dried and crushed strammonium into cigars and cigarettes and inhale the smoke they created. It was a very effective medicine for it's time.



But, now we know different. Now we know that asthma is a disorder of an overactive immune system. It's caused by mutated immune genes. This causes these genes to make extra proinflammatory cytokines and chemokines and other mediators of inflammation. This overactive immune response leads to chronic underlying airway inflammation that makes airways hypersensitive to asthma triggers.

I will be honest, I was angry when a doctor told me my asthma was caused by anxiety. I wasn't told it was all in my head. But, I was told that anxiety made my asthma worse. I was told that anxiety contributed to my asthma. So, I understand the initial frustration at these old theories. But, the good thing about theories is it gives some direction to researchers. Without theories researchers have nothing to aim for. So, old theories, even incorrect, are good in this way.

Also, we are only on the cutting edge of asthma wisdom. The same with COPD. Asthma has been around a lot longer as a known disease So, much more is known about asthma. But, the idea that asthma and COPD are caused by the immune system is very important. It gives researchers a new theory to aim to prove -- or maybe even disprove.

And I think they are finally on the right track. All those old theories proved themselves false over time. Research to prove them lead to lots of dead ends. So, researchers no longer have to dedicate money to prove what asthma is not. And hopefully the current path will lead to better, stronger medicines for treating asthma. And, who knows, maybe even an eventual cure.