Reactive airways dysfunction syndrome

A form of irritant-induced asthma also known as occupational asthma

Reactive airways dysfunction syndrome (RADS) describes breathing problems that develop after a single exposure to high levels of an irritating vapour, fume, or smoke.

In general, the development of respiratory symptoms is rapid, within the minutes or hours after a single accidental breath of a high concentration of irritant gas, aerosol, or smoke. Some experts classify RADS as occupational asthma.

Key points

  1. Moments after inhaling the irritant, asthma-like symptoms such as chest tightness, wheezing, cough and dyspnoea (shortness of breath or breathlessness) develop.
  2. Symptoms can range from mild to severe or even fatal.
  3. In some cases, it can be hard to diagnose and is assumed to be asthma.
  4. Airway hyper-responsiveness that can remain for a long time (months to years).
  5. RADS can be an extremely debilitating condition. In some people, everyday smells and irritants like smoke, dust, petrol fumes, laundry detergent or perfume can trigger a life-threatening reaction.

Risk factors

Anyone can get RADS. It is caused by a high exposure to chemicals, smoke, fumes or vapours. This can be from a chemical spill, leak or a fire. RADS usually develops quickly and often symptoms stay for a long period of time.

People in certain occupations are at higher risk of exposure, such as:

  • fire fighters
  • cleaners
  • farmers
  • police
  • welders
  • emergency services.


Common triggers include:

  • petrol fumes
  • wood Fire
  • smoke
  • perfume
  • cleaning chemicals.


If you have developed asthma following exposure to an irritant, see your doctor for accurate diagnosis and treatment advice.

Treatment for RADS is no different to treatment of asthma, with the use of medications to help relieve and prevent symptoms.  Alongside medication, avoidance of triggers is an essential part of managing RADS.

Preventing exposure to triggers

Ongoing exposure to irritants can cause continued inflammation and excess mucus production in the airways, and can make your symptoms worse. Where possible, avoid using substances that can trigger RADS. If the substance is essential to your daily life or work, it may be possible to substitute it for one that is less irritating. You may also be able to reduce exposure by using an exhaust ventilation system or an approved respiratory protection device.

Learn more

Common triggers of people living with RADS RADS Foundation
International support network RADS Foundation


  1. Reactive airways dysfunction syndrome and irritant-induced asthma. UptoDate, August 2014
  2. Airways Dysfunction Syndrome, Irritant-Induced Asthma: Diagnosis And Management Medscape General Medicine
Credits: Health Navigator. Last reviewed: 18 Jan 2015