Pathophysiology of Asthma

Pathophysiology of Asthma


Asthma is a chronic disease of the lungs characterized by sporadic attacks of shortness of breath, wheezing, and coughing. It is one of the most common diseases affecting respiration. An asthmatic may have sudden, sharp attacks that might leave a person gasping for breath. It affects all races and both sexes equally. To under Asthma, first, we need to understand the Pathophysiology of Asthma.

Asthma Pathophysiology


People with Asthma invariably have an overreaction of the immune system. The overreacting of the immune system is caused by allergy in your respiratory tract. This allergy is responsible for producing signs and symptoms of Asthma.


The function of the immune system is to produce inflammation. Inflammation protects you. Unfortunately, in the case of Asthma, it overreacts to have this inflammatory response than usual.

People who have Asthma, developed because of allergy have an exaggerated immune response. The inflammation caused by the excessive immune response is primarily found in the bronchioles. Bronchioles of the lungs are smaller airways, and they are made of smooth muscles, and the muscles’ function is to contract and relax.


Asthma primarily affects the lower airways and specifically the bronchioles.

To understand Asthma Pathophysiology first, we need to understand the anatomy of the respiratory tract.


The airways are very Vascular, that means it is having lots of blood vessel and arteries. It even has Goblet cells, which secretes mucus. Mucus acts as a protective agent by trapping inhaled toxins or allergens. Then the cilia move those toxins back to your throat.


The bronchial wall is very vascular, and it is also made up of smooth muscles.

Inflammation is developed by vasodilation, where the blood vessels, arteries, and arterioles get dilated. When they widen, the diameter of the bronchioles gets smaller.


Due to the contraction of the bronchioles, airway resistance increases. As a result, the person in this condition has to breathe harder, putting more labour into raising the ribcage to overcome airflow resistance.


Even the goblet cells become overactive and start secreting more mucus than normal, so the airways become narrower, increasing the air resistance.

The immune system cells, also called leukocytes, release leukotrienes that cause bronchial muscles to spasm.


In a normal airway, airflow in the lower airway is laminar. But in Asthma, the bronchial walls muscle bands tighten around the airway and goes to spasm, causing turbulent airflow. This turbulent airflow produces the wheezing sound, which is predominant in Asthma. 

This phenomenon is the basic Pathophysiology of Asthma.


Asthma Pathophysiology


Types of Asthma


Types of Asthma are classified by the things that triggered the Asthma attack.


Atopic Asthma 

Atopic Asthma is Extrinsic Asthma which means asthma episode is triggered by the environment triggers, such as smoke, pollution, pollen, etc.

Non-Atopic Asthma

 Non-Atopic Asthma, also known as Intrinsic Asthma. This type of Asthma refers to the inflammation and constriction of the airways that is not caused by the environment.

Drug-Induced Asthma

 Some peoples with Asthma is Sensitive to certain drugs like aspirin and other painkillers etc.

Occupational Asthma

 Occupational exposure to some chemicals, fumes, gas, organic or chemical dust, etc.

Exercise-Induced Asthma

 Strenuous exercise causes shortness of breath, wheezing, and may trigger Asthma.

Types of Asthma


Extrinsic Asthma


Extrinsic Asthma is the most common form of Asthma; it is also called Allergic Asthma or Seasonal AsthmaExtrinsic Asthma is caused by an adverse reaction to things like house dust, pollen, feathers, animal dander, and certain foods. Stong odours or smoke may also cause its attacks. Asthma is often linked with hay fever, another type of allergyExtrinsic Asthma starts at an early stage during childhood. It involves inflammation mediated by systemic IgE (immunoglobulin E) production. 


Extrinsic Asthma is Episodic, which means the consequences of Asthma increase serially.

Cold weather is one of the most common triggers of allergic diseases, which may include nasal allergy and Asthma. Seasonal Asthma is most profound during the winter season. This type of Asthma is genetic.

Extrinsic Asthma


Adult-Onset Asthma


At least 30% of Adult-onset Asthma is triggered by allergies. 

Here are some triggers of Adult-onset Asthma. One can get Asthma at the age of 40 to 60 or even later in life.

  • Hormonal Fluctuation: Hormonal fluctuation in an adult can onset Asthma.
  • Exercise: Strenuous exercise can trigger Asthma in adults.
  • Exposure to second-hand smoke
  • Eczema
  • Occupational Exposure: Exposure to certain chemicals or certain materials can trigger Asthma.
  • Viral Infection

 Asthma Risk Factors


Asthma Risk Factors are anything that can cause inflammation and constriction of the airways.

How do you know you have Asthma?


If you develop certain symptoms, then it can be indicative that you may have Asthma.

  • Shortness of breath
  • Tightness in the chest
  • Difficulty in breathing
  • Difficulty in doing physical activities
  • Cough

Is Asthma Genetic?


Most of the time, it is inherited, especially for Extrinsic AsthmaIt is genetic someone in the family usually has a history of Asthma. Genetic factors have an important influence on the development of atopy severity of disease expression and inflammation. 

Can you develop Asthma?


Asthma can develop at any time in life. If you have a history of allergies or someone in your family has Asthma, then you are most likely to develop this disease.

Can Asthma be Cured?


There is no cure for Asthma, but you can control it very well with proper medication and avoiding environmental triggers.

Leave a Comment