Many Changes To How Asthma Is Classified

Over the past 20 years, there have been many changes to the ways asthma is classified. The most significant change is that away from the idea of asthma as a homogeneous disease. The shift was toward the idea of asthma as a heterogeneous disease. This lead to the redefining of asthma as a single disease to one with many subgroups (phenotypes /endotypes).

As a homogeneous disease, all asthmatics were treated the same. They were all treated as allergic asthmatics. They were all assumed to have allergies. And the treatment for them were inhaled corticosteroids and bronchodilators. These were the recommendations of many of the original asthma guidelines from the late 1980s.

This strategy worked great for about 85-90% of asthmatics. It helped them obtain ideal, or at least better, asthma control. The problem was that about 10-15% continued to have poorly controlled asthma despite optimal treatment. And it was treatment for this group that encompassed a majority of the overall healthcare cost for treating asthma as a disease nationally and worldwide.

So, this group encompassed a majority of asthma research funds over the past several years. And this research seems to be showing promise. The best evidence of this is the discovery of over 100 asthma genes. Researchers now believe every asthmatic has a random assortment of these genes. And that may explain why each asthmatic experiences it in different ways. For instance, one doctor once chimed, "If you've seen one asthmatic you've seen one asthmatic."

Still, this research has resulted in the creation of asthma subgroups. Fancy terms for this are phenotypes and endotypes. Subgroups loop asthmatics with similar presentations into certain groups. For instance, childlhood-onset and allergic asthmatics are lumped under the subgroup Allergic Asthma. The 10-15% of asthmatics who continue to have poorly controlled asthma despite the best treatment are lumped under the subgroup severe asthma.

Some asthma subgroups are now well accepted. These include allergic asthma, exercise induced asthma, eosinophilic asthma, severe asthma. Others are not so well accepted, such as neutrophilic asthma, premenopausal asthma, obesity associated asthma, Aspirin exacerbated respiratory disease, and nervous asthma. For these less recognized subgroups you'll see various names bandied about mainly due to the fact these are poorly understood.

And that is the reason for doing more research, so all of the different subgroups can be better. understood. And when they are understood better, specific treatments may be developed to better help asthmatics of a given subgroup. And this will lead to better, more specific guidelines for each subgroup. This is all in an effort to help all asthmatics obtain ideal asthma control.