Reactive airways dysfunction syndrome

Also known as reactive airway disease

Reactive airways dysfunction syndrome (RADS) describes breathing problems that develop after a single exposure to high levels of an irritant gas, smoke, fumes or vapours.

On this page, you can find the following information:

Key points about RADS

  1. Symptoms usually develop rapidly within 24 hours after the exposure.
  2. RADS is a form of irritant-induced asthma, and as it is mostly caused by irritants in the workplace, it is often classified as occupational asthma.
  3. Moments after inhaling the irritants, asthma-like symptoms such as chest tightness, wheezing, cough and dyspnoea (shortness of breath or breathlessness) develop.
  4. Symptoms can range from mild to severe and can last for months to years, or even be fatal.
  5. It can be hard to diagnose RADS and often the condition is assumed to be asthma.
  6. RADS can be an extremely debilitating condition as everyday smells and irritants like smoke, dust, petrol fumes, laundry detergent or perfume can trigger a life-threatening reaction.

What are the causes of RADS?

Anyone can get RADS. It is caused by a high exposure to irritant gas, 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 who are in certain occupations are at higher risk of exposure to irritants. These include:

  • firefighters
  • cleaners
  • farmers
  • police
  • welders
  • emergency service workers
  • pulp mill workers.

Common irritants include:

  • petrol fumes
  • wood fire
  • smokes
  • perfumes
  • cleaning chemicals such as chlorine.

What are the symptoms of RADS?

Symptoms of RADS typically develop within 24 hours (usually less) of exposure to high concentrations of irritants and can last for long periods of time, eg, months to years, even after the irritants are removed. The symptoms are similar to asthma which is why RADS is often misdiagnosed as asthma.

Common symptoms of RADS include:

Contact your GP or go to the nearest emergency department immediately if you have the symptoms above.

It is also important to let your doctor know you were exposed to a high concentration of irritant gas, smoke, fumes or vapours before your symptoms developed.

How is RADS diagnosed?

Your doctor will ask you some questions related to your symptoms. These include about:

  • any exposure to irritants such as gas, smoke, fumes or vapours in high concentrations
  • whether you have been diagnosed with asthma or other lung conditions previously
  • if your symptoms developed suddenly or within 24 hours after you were exposed to irritants
  • your occupation.

Your doctor will examine your lungs and do some tests such as blood tests to check your oxygen levels, a chest x-ray or a spirometry if necessary.

Sometimes, RADS may only be diagnosed after multiple follow-up visits to your doctor. You may need to ask to be referred to a specialist (pulmonologist or respiratory specialist) who is familiar with RADS to get a correct diagnosis.

How is RADS treated?

Treatment of RADS depends on whether it is acute or chronic.

If you have developed any of the symptoms above within 24 hours of exposure to an irritant, you should contact your GP or go to the nearest emergency department immediately. Asthma medicines such as bronchodilators or inhaled corticosteroids are given in an acute situation. 

As symptoms of RADS can last for months or years, for long-term management of the condition, it is helpful to seek a referral to a pulmonologist or respiratory specialist who is familiar with RADS for treatment advice.

Treatment for persistent symptoms is mainly avoidance of exposure to irritants, including those that triggered RADS, cigarette smoke and any other substances that you have allergy reactions to that are not related to RADS.

Medicines such as bronchodilators and inhaled corticosteroids may also be needed to treat asthma-like symptoms, following the Global Initiative for Asthma (GINA) step-wise method of using a low dose that is increased or decreased as needed.

If you were exposed to irritants in your workplace, you can safely return to work as long as your symptoms are well controlled and safety measures are taken to avoid high level of exposure to irritants.  

How can I prevent the exposure to irritants?

Ongoing exposure to irritants can cause continued inflammation and excess mucus production in your airways, and can make your symptoms worse. Where possible, avoid using substances or irritants that cause your condition.

If the substance or irritant is essential to your daily life or work, it may be possible to replace it with something that is less irritating. You may also be able to reduce exposure by using an exhaust ventilation system or an approved respiratory protection device.

Talk to your employer if the irritants are found in your workplace to find out ways to reduce your exposure.

What support is available with RADS?

Worksafe NZ is a New Zealand-based organisation that provides general information and resources regarding workplace health and safety. You can also makes claims in relation to work-related health problems through ACC NZ, with a range of possible benefits and support. 

Learn more

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


  1. Reactive airways dysfunction syndrome and irritant-induced asthma UptoDate, US, 2022
  2. Airways dysfunction syndrome, irritant-induced asthma – diagnosis and management Medscape General Medicine, US
  3. GINA strategy 2020 – management of asthma Global Initiative for Asthma, US, 2020

Reviewed by

Dr Helen Kenealy is a geriatrician and general physician working at Counties Manukau DHB. She has a broad range of interests and has worked in a variety of settings including inpatient rehabilitation, orthgeriatrics and community geriatrics.
Credits: Health Navigator Editorial Team. Reviewed By: Dr Helen Kenealy, geriatrician and general physician, Counties Manukau DHB Last reviewed: 11 Jan 2021