Introducing Early And Late-Onset Asthma
You may be familiar with terms like Childhood-Onset Asthma and Adult-Onset Asthma. Many researchers now scoff at these old terms and prefer to use terms like Early-Onset Asthma and Late-Onset Asthma. This change may seem trivial, and it probably is. But, there is a good reason for the change. Allow me to explain.
So, when does Childhood-Onset Asthma end and Adult-Onset Asthma begin?
This seems to be open to much speculation. Some say it is 17, others 18, and others 20 or 21. I have seen them all. I have even seen 40 as the cut-off age.
Traditionally, Childhood-Onset Asthma is asthma diagnosed in childhood, and Adult-Onset Asthma is asthma diagnosed in adulthood.
This was a distinction made by the great asthma doctor, Dr. Francis Rackemann, in 1940. He noted that those diagnosed with extrinsic (now called Allergic Asthma) were more likely to be diagnosed in childhood, and those diagnosed with intrinsic (Now called Non-Allergic Asthma) were more likely to be diagnosed in adulthood. 1
However, now that researchers have defined Premenopausal Asthma and Late-Onset Eosinophilic Asthma, both of which can be diagnosed in childhood and adulthood, some modern researchers seem to suggest that the cut-off age should be 12. 2
Allow me to explain.
About 20 or so years ago, researchers recognized that a certain percentage of asthmatics did not respond well to traditional asthma medicines. This lead to further research which leads to researchers defining all these new asthma subgroups. Two of which are Pre-menopausal and Late-Onset Eosinophilic Asthma.
I believe it was these two asthma subgroups that lead to the change into lowering the cut-off age between early and late onset to 12. And I think, but I’m not certain, that this might have also inspired the change from Adult-Onset Asthma into Late Onset Asthma.
My theory, in this case, is that these changes were made because a female child aged 12, who very likely could be diagnosed with premenopausal asthma, is not necessarily an adult yet.
Hence the change from Adult-Onset Asthma into Late-Onset Asthma. Late-Onset meaning after the age of 12, or after the beginning of puberty. I think the key word here is puberty. I think this distinction is important because asthma diagnosed after the age of 12 is different from asthma diagnosed before the age of 12.
So, if a female child is diagnosed after puberty, the child would benefit by her physician looking into other asthma subgroups other than just Allergic Asthma. A proper diagnosis of Premenopausal Asthma, if this is the case, would bode well for this child.
And, of course, since adult-onset was changed to late-onset, then it only made sense to change childhood-onset to early onset.
Another theory to explain the change is Late-Onset Eosinophilic Asthma. Adolescents are often diagnosed with this asthma subgroup. Changing the cut-off to 12 acts to differentiate Early-Onset Allergic Asthma with Adolescent-Onset Eosinophilic Asthma. 2
This distinction is important, be use the causes, severity, and outcomes of these two subgroups of asthma are different. How they are treated may also differ.
Early Onset Allergic Asthma is caused by allergens. Children are usually exposed to these early in life, like, before the age of 12. In fact, I read recently that most children are exposed to allergens before the age of 6.
Airways inflammation is eosinophilic, and this is what makes airways hypersensitive to asthma triggers. This inflammation subsides between episodes. It also responds well to inhaled corticosteroids, so it’s usually easy to obtain good asthma control.
Late-Onset Eosinophilic Asthma is usually non-allergic and is more likely to be caused by something other than allergens, such as chronic exposure to Diesel fuel. Airway inflammation is eosinophilic, but eosinophil levels remain elevated even between episodes. A diagnosis is more likely later in life, such as after the age of 12. It is more difficult to control compared with early-onset asthma. 2
Hence the change from Childhood-Onset Asthma into Early Onset Asthma.
In fact, it was in 2004, Miranda and associated recommended using the terms Early and Late-Onset Asthma. A few years later, in 2008, Late-Onset Eosinophilic Asthma was first defined by the medical community. 1
So, this might explain why you’ll often see, in more recent articles and books regarding asthma, the terms Early-Onset and Late-Onset as opposed to Childhood-Onset and Adult-Onset. And of course, the cut-off between the two will be 12, or at least adolescents diagnosed after puberty.
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