What Is Reactive Airway Disease?

Scrutinizing the confusing and possibly outdated term

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A woman with breathing difficulties.
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Reactive airway disease (RAD) is a general term used to describe a reaction in which the bronchial tubes of the lungs overreact to an irritant, triggering wheezing and shortness of breath. While it's easy to assume that RAD is the same thing as asthma, RAD is actually no more than a placeholder for almost any restrictive respiratory event that has not been officially diagnosed. In other words, it's simply a classification of symptoms related to any number of conditions, including asthma, chronic obstructive pulmonary disease (COPD), and certain bronchial infections.

The term RAD is most commonly applied in pediatrics when a child experiences asthma-like symptoms but is too young to undergo a bronchial challenge test or other forms of diagnostic evaluation.

Controversy and Confusion

While the term RAD is not meant to confuse people, it frequently does. The confusion stems in part from the term "reactive airway dysfunction syndrome (RADS)" which was coined in 1985 by American pulmonologist Stuart Brooks to describe a one-off, asthma-like reaction to smoke, fumes, or corrosive gases. Today, "occupational asthma" and "irritant-induced asthma" are more commonly applied, with some experts questioning whether RADS is even a real and distinct clinical entity.

Since that time, the shortened "reactive airway disease (RAD)" has been increasingly used to describe a wide range of diseases that cause asthma-like symptoms. The problem is that it is not a medical term per se and has different definitions depending on who you speak to. Some doctors will use RAD to describe diseases that cause reversible airway narrowing, while others will include COPD, which is clearly not reversible. To add even more confusion, some—including medical professionals—will misuse RAD as a synonym for asthma.

For their part, the American Academy of Allergy, Asthma, and Immunology (AAAAI) has labeled the term "imprecise" and "lazy," believing that it suggests a diagnosis in the absence of an actual investigation.

Others contend that term has its appropriate usage, particularly in pediatrics or emergency care. Moreover, the very non-specificity of the classification, some argue, is meant to incite clinicians to look beyond the obvious causes and explore less common (and potentially more serious) explanations for symptoms.

Symptoms

You could be said to have RAD if you are experiencing wheezing, shortness of breath, and a persistent, productive cough. This cluster of symptom is triggered by a common physiological response, whether you have asthma, COPD, and other reactive respiratory conditions:

  • Breathing restriction is caused when the smooth muscles of the lungs are hyperresponsive, cause airways to contract and narrow.
  • Inflammation is caused when the immune system releases histamine to dilate the blood vessels in the lungs. This causes swelling and further narrowing of air passages.
  • Excessive mucus is produced in response to both of the conditions, clogging the airways and tiny air sacs of the lungs (called alveoli).

Depending on the severity of the response, symptoms can range from mild to life-threatening.

Causes

Again, RAD is not a diagnosis but rather a characterization of physical symptoms. It serves only as the launching point for an investigation, the direction of which can vary based on your age, medical history, symptoms, and events leading up to the attack.

The short list of common and uncommon causes include:

  • Irritant-induced asthma, commonly affecting bakers, farmers, grain elevator operators, metal workers, plastic workers, and woodworkers
  • Pulmonary embolus, a blood clot in the lungs often occurring in people with heart disease, cancer, or who have had recent surgery
  • Upper respiratory viral infection, in which asthma-like symptoms are accompanied by high fever, chills, and body aches

Diagnosis

The approach to diagnosis is as varied as the possible causes. By and large, doctors will pursue in investigations based on the diagnostic clues noted in the initial exam.

These may include:

In pediatric cases, RAD may be notated in the infant's medical records if no apparent cause is found in the early investigation. The aim of the notation is to ensure that the baby's condition is monitored until such time as more definitive diagnostic tools can be used.

Treatment

There are no clear treatment guidelines for reactive airway disease. In emergency situations, the classification would help direct rescue efforts, which may include:

In such situations, the term RAD provides emergency room staff with a shorthand of symptoms once the patient is delivered by ambulance personnel.

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