Reactive Airway Disease in the Clinical Setting

The use of the term “reactive airway disease” has shown a significant increase amongst health care providers in recent years. Originally coined in the 1980s as a way to describe a symptom of asthma (airway hyperreactivity), it has become common to use these terms interchangeably. However, they are different in definition and it is integral to make distinction between the two diseases in order to avoid confusion in the clinical setting.

What is reactive airway disease?

Reactive airway disease, often abbreviated as RAD, is a general term that many physicians use to label patients who have symptoms similar to those of asthma. There is no accepted definition of RAD, which leads to ambiguity in the necessary symptoms needed for “diagnosis.” Most patients labeled as having RAD have a history of coughing, wheezing, production of sputum, and dyspnea (shortness of breath).

The term started to appear in medical literature in the 1980s and was originally only used to describe airway hyperreactivity, a common feature of asthmatic patients. Airway hyperreactivity is a specific term that describes those who have increased bronchoconstrictor reactions to different stimuli that would not generally elicit a response in healthy people. These stimuli can include methacholine, histamine, and distilled water.

Despite the increasing use of the term RAD in both clinical lexicon and literature, RAD remains unrecognized by a large number of associations, such as the American Academy of Pediatrics, the American Thoracic Society, or the National Heart Lung and Blood Institute. There is also no listing of RAD in any medical journal.

What’s the difference between reactive airway disease and asthma?

While the characteristics of RAD and asthma overlap, they are not the same disease. Physicians will often label their patients with RAD when they are hesitant to definitively diagnose them with asthma. This can happen for a variety of reasons, with the most common being that the patient is either an infant or a toddler. In young children, asthma and viral bronchiolitis are virtually indistinguishable from one another. Many children wheeze during infancy, yet only ⅓ of them actually go on to develop asthma later on. Asthma tests also tend to be less accurate when a patient is under the age of five, leading to difficulty in obtaining quality results from a pulmonary function test. In addition, history for young children is much harder to obtain and there is a often a perceived “negative connotation” with asthma diagnoses. All of these factors together result in hesitancy from many physicians to make a real and definitive diagnosis of asthma for young children. As for adults who are labeled with RAD, doctors may use the term for the individuals who have no prior history of asthma. Although the terms are increasingly used interchangeably, there is still an important distinction between asthma and reactive airway disease.

What is reaction airways dysfunction syndrome?

It is essential to distinguish RAD from reactive airways dysfunction syndrome, or RADS, due to their similar acronyms. RADS is defined as an asthma-like illness that results from high exposure to fumes, vapor, or smoke. The individual will suffer from lung damage and this may be manifested by coughing, wheezing, and shortness of breath. While the initial exposure can be brief, the symptoms of RADS may persist for years after that first encounter. One main difference between asthma and RADS is that RADS tends to occur after just one exposure to the inhalants and without any prior sensitization. In addition, although the symptoms of RADS are very similar to those of asthma, they may be resolved.

Despite the fact that RADS is more widely recognized than RAD, some physicians still also debate its spot in the clinical setting. Some scientists argue that it is not a real clinical syndrome. However, it is seen as distinct by several associations, including the American Thoracic Society and the American College of Chest Physicians.

Problems with using the term “reactive airway disease”

There is inevitable debate about the growing use of RAD in the clinical setting, with some medical professionals being baffled as to how we have let it slip into our medical lexicon. What is perhaps the largest issue with its use amongst physicians is the ambiguity of its meaning. Since RAD has no distinct definition, the symptoms that characterize it are often inconsistent and this can lead to confusion about what a patient is actually experiencing. It is essential to preserve the accuracy and integrity of asthma and airway hyperreactivity as diagnostic terms in clinical literature and some argue that using RAD as a diagnosis will only complicate research on asthma in the context of clinical research and epidemiology. There is also the dispute that labeling a patient with RAD gives providers a fabricated sense of security that they have made a diagnosis, when in actuality no recognizable conclusion has been made.

Weihong Zheng, M.D.