Phases Of An Asthma Attack, Explained

You may know the symptoms of an asthma attack, but do you understand why it’s occurring in the first place? We explore the two phases of an asthma attack and how you can spot the signs.

Published: Tuesday 02 August 2022

Understanding Asthma

Many people in the UK have asthma - you may have it yourself or know someone who does. External triggers or allergens can sometimes exacerbate these symptoms to what is known as an asthma attack. Although asthma attacks involve complicated internal immune responses, it's imperative that you understand these processes as this will allow you to recognise the symptoms and intervene early. Knowing these immune responses will also leave you better prepared for a future asthma attack, so you can try to prevent it.

What is an asthma attack?

If you suffer from asthma, you may be used to experiencing symptoms during your everyday life such as shortness of breath, wheezing and coughing. Exposure to an asthma trigger can suddenly increase the severity of these symptoms, leading to breathing difficulty and restriction of airflow from the muscles in your airways. This response from the immune system is an attempt to stop whatever 'harmful' substances it believes is currently invading the body. This process is known as an asthma attack (or asthma exacerbation) and its symptoms can be life-threatening if not treated.

Asthma symptoms can be managed daily with asthma treatments such as Ventolin Inhalers which help to open up the airways by relaxing respiratory muscles to ease airflow. The effective management of asthma triggers and symptoms can help to reduce the risk of an asthma attack.

What causes an asthma attack?

Asthma attack symptoms are caused by the exposure of an asthma trigger or allergen to the immune system, which then reacts by initiating the onset of asthma symptoms. These triggers can vary drastically and affect asthma sufferers differently.

Some common triggers include:

  • Pollen
  • Pet hair
  • Mould and dust mites
  • Smoke
  • Stress
  • GERD (gastroesophageal reflux disease)

Some triggers are more common in certain seasons: for example, experiencing asthma during winter is known to bring with it several common asthma triggers, similar to asthma experienced during summer. Certain foods can also have an impact, so it's important to consider an asthma diet or monitor your eating habits closely.

Although anyone with asthma is at risk of experiencing an asthma attack, some people may be more at risk based on whether:

  • You've previously had a severe asthma attack.
  • You've previously been admitted to the hospital or A&E for asthma.
  • You've previously required intubation for asthma.
  • Your asthma symptoms 'sneak up on you' before you're able to notice the severity of them.
  • You have other chronic health conditions that may worsen your asthma.

What are the phases of an asthma attack?

The phases of an asthma attack refer to processes occurring inside the body whilst an asthma attack is ongoing. They are usually divided into two categories: the early phase and the late phase [1]. The phases may differ in symptoms and duration depending on the individual and surrounding environment, but they can sometimes be difficult to differentiate. Phases of an asthma attack are different to stages of asthma. This term is commonly used to describe the pathophysiological stages of asthma progression: intermittent, mild persistent, moderate persistent, and severe persistent.

Early phase asthma attack

At this stage, the body has likely just come into contact with an asthma trigger or allergen that has been inhaled into the lungs. The foreign allergen will be detected by immunoglobulin antibodies - one of the first lines of defence from the body's immune system - that are attached to mast cells. Once the immunoglobulin antibodies alert the mast cells of the foreign presence, the mast cells release a series of chemicals and compounds in an attempt to fight off the allergen, including:

  • Prostaglandins (lipid compounds with inflammatory effects including vasodilation and internal temperature increases).
  • Histamines (neurotransmitters that boost blood flow to the affected area causing inflammation).
  • Cytokines (proteins that increase mucus production in the airways).
  • Leukotrienes (biochemical mediators that increase airway mucus production and contract smooth muscles in the airways, restricting airflow).


During the early stages of an asthma attack, you may experience bronchospasms; this refers to the restriction of muscles in the airway, which causes less airflow to pass through and your breathing to become more difficult. You may struggle to take a full breath, begin wheezing or experience bouts of coughing fits.

Late phase asthma attack

The second stage of an asthma attack, also known as the late phase, is usually experienced by around 60% of asthmatics who experienced the early phase [2]. It typically occurs several hours after the initial immune response. At this stage, the symptoms of an asthma attack will be much more aggressive and noticeable due to the duration of time bronchoconstriction has been occurring. After being notified during the early phase, different immune response cells are activated and travel to the lungs.

These immune response cells include:

  • TH2 cells (immune system response cells that increase inflammation)
  • Eosinophils (white blood cells that also cause swelling and inflammation)
  • Basophils (another type of white blood cell that binds with immunoglobulin antibodies, causing the basophils to release more histamine and cytokines)
  • Neutrophils (white blood cells that also fight infections, but are known to destroy airway epithelial cells and cause further inflammation in the airways)


At this stage, the presence of the immune response cells causes more severe bronchoconstriction and breathing difficulties. Symptoms similar to the early phase may be present such as wheezing and coughing, but it is more likely that these will be amplified, leading to symptoms like increased coughing (and coughing up mucus), a tight-chest, and difficulty breathing. Depending on the original trigger for the asthma attack, you could also experience a sore throat or digestive issues.

What to do during an asthma attack

Due to the severity of asthma attacks, keeping track of the progression of symptoms from early phase to late phase is crucial, as the sooner an asthma attack is detected the easier it is to treat. The NHS recommends the following steps for someone experiencing an asthma attack:

  1. Try to remain calm and sit up straight to improve airflow.
  2. Inhale one puff of your reliever inhaler every 30 to 60 seconds, until you have completed 10 puffs.
  3. If you are not feeling better after 10 puffs, call 999 for an ambulance.
  4. If the ambulance has not arrived within 10 minutes and your symptoms are still not showing signs of improvement, repeat step 2.
  5. If the ambulance has still not arrived after repeating step 2, and your symptoms are still not improving, call 999 again immediately.

If your symptoms begin to improve after step 2 and you feel you do not need to call for an ambulance, you should still book an urgent same-day GP appointment or see an asthma nurse, as your body can still transition into late phase up to 8 hours after your initial reaction.

The body goes through a lot of complicated processes and immune responses during an asthma attack. Although these can be confusing, the most important thing to remember is how these internal processes are reflected in external symptoms so you can recognise them, understand which phase of an asthma attack you or someone you know may be in, and seek treatment as quickly as possible!

Amber Mitchell-Hanna

Written by: Amber Mitchell-Hanna

Pharmica Medical Writer

Amber is an experienced writer and content specialist, graduating from De Montfort University with an LLB & an MA in Investigative Journalism.

She particularly enjoys creating informative health content, debunking medical misconceptions, and championing inclusion and diversity.

Find out more about how we ensure the accuracy of our content with our content guidelines.

How to Manage Winter Asthma Triggers
How to Manage Winter Asthma Triggers