What is Adult Onset Asthma?

by John Bottrell Health Professional

Adult Onset Asthma (AOA) is the term used to describe cases of asthma that are diagnosed after the age of 20, although they are usually not diagnosed until after the age of 40. Sometimes, when diagnosed after the age of 50, it is called Late-Onset Asthma.

Here are some facts to consider.

Intrinsic Asthma.
It's usually intrinsic, meaning it's caused by something other than allergies. Usually it results from long term or repeated exposure to any of the following:

  • Hormones from menopause

  • Pollution in the air

  • Chemicals in the air at work or home (such as those in common household cleaners)

  • Chemicals in cigarette smoke (tar, arsenic, cadmium, formaldehyde, chromium, etc.)

  • Lung infections (mainly the viral type)

  • Non-steroidal anti-inflammatory (NSAID) medicine (such as Aspirin)

  • Hormones released from fat tissue (obesity or high fat foods)

  • Vigorous exercise (especially during freezing conditions).

Extrinsic Asthma. sometimes extrinsic, meaning it's A modern term for this is "Allergic Asthma," and it's much more common in Childhood Onset Asthma than AOA.
However, researchers have learned it is still possible to develop allergies in adulthood.
Allergic Asthma is less likely to cause chronic airway changes. This means it's usually milder and easier to control with traditional asthma medicines, such as corticosteroids.

Women. According to the American Lung Association, 10.8 million males and 15.1 million females have asthma. This shows that women are more likely to be diagnosed than men.
This trend is reversed in childhood, where boys are more likely to have it than girls. The reason for this remains a mystery; although, one theory attributes this to hormones from pregnancy and menopause resulting in AOA.

Severity. Because it's usually intrinsic, and the result of repeated exposure to some substance in the body or in the air inhaled, it's more likely to cause airway changes (airway remodelling), such as a thickening of airway walls. This makes it so those diagnosed in adulthood tend to lose lung function more rapidly than children.
This also might explain why they have an increased likelihood of responding poorly to traditional asthma medicines, such as corticosteroids. They have a greater risk of having more severe asthma than those diagnosed in childhood.

The mainstay treatment is corticosteroids.
However, due to chronic airway changes, some adult asthmatics will respond poorly to corticosteroids.
This may require creative treatment options that may vary from patient to patient.
Also complicating treatment are other chronic diseases that may be present.

Adults tend to have other ailments due to aging or environmental exposure. Examples include COPD, heart disease, diabetes, hypertension, sinusitis, upper respiratory infections, and nasal polyps. These may make asthma difficult to treat and control.
Some cause breathing trouble, making an asthma diagnosis difficult.

It's a myth that a person can outgrow their asthma.
However, some children do seem to have their asthma disappear for a while, or go into remission, as they grow older. This is less likely to occur among those diagnosed in adulthood.
This may be due to the greater likelihood of chronic airway changes developing in adults. It may also be due to other factors yet unknown.

Asthma was once thought to be a disease of childhood.
This meant that most cases of AOA were misdiagnosed as some other lung disease, such as COPD.
More than likely this lead to suboptimal treatment.
With improved wisdom, physicians are now much better at both diagnosing and treating adult asthma.

It's important for physicians to understand the difference between childhood and adult onset asthma.
When a person develops a disease it may impact how it is diagnosed and what treatment options will work best.

Further Reading:

John Bottrell
Meet Our Writer
John Bottrell

John Bottrell is a registered Respiratory Therapist. He wrote for HealthCentral as a health professional for Asthma and Chronic Obstructive Pulmonary Disease (COPD).