Asthma - All You Need To Know

Written by Clement Mbah, MD, PhD, MBChB | Published on October 09, 2021

Asthma is a common chronic disease of the airway with worldwide prevalence. About 300 million people are said to be affected by asthma worldwide.

The World Health Organization (WHO) defines asthma as a chronic condition affecting children and adults characterized by recurrent narrowing of the air passages in the lungs due to inflammation and tightening of the muscles around the small airways.

Asthma is a non-communicable disease and the most chronic disease among children. The World Health Organization estimated that about a 262million people were living with asthma in 2019, and asthma had caused 461000 deaths. [1]

Natural History And Epidemiology

The prevalence of asthma has steadily increased over the last century, both in the developed and developing world, but it is still commoner in the developed world. In the USA, asthma affects 5-10% of the population or an estimated 23.4million persons, including 7 million children.

The exact incidence and prevalence of Asthma in Nigeria are unknown. However, it is generally accepted that in a given community about 5-10% of children have asthma, while a further 3-5% have undiagnosed asthma.

In a school survey in Ibadan, Sofowora and Clark, (1970) found the prevalence of asthma to be 2.4%. Three decades later, Falade “et al.” using an ISAAC questionnaire found a rate of 10.7% in the same community.

Trends suggest an increase in the morbidity of asthma, especially in children younger than 6 years. Asthma predominantly affects boys in childhood than girls, with a male to female ratio of 2:1 until puberty, when the male to female ratio becomes 1:1.

Asthma prevalence is greater in females after puberty, and the majority of adult-onset cases diagnosed in persons older than 40 years occur in females. Boys are more likely than girls to experience a decrease in symptoms in late adolescence. [2]


Causes And Risk Factors

The exact cause of asthma is not known, however different factors have been said to contribute to increasing the risk of developing or worsening asthma. They include;

  • Family history of asthma (asthma is more likely in a person if other family members have asthma).
  • Allergies (examples include, house dust, mites, animal allergens, food allergens)
  • Perinatal factors (prematurity, low birth weight, maternal smoking).
  • Respiratory tract infections (usually viral origin).
  • Unaccustomed exercise
  • Environmental pollutants (tobacco smoke)
  • Irritants (household sprays, paints)
  • Obesity
  • Emotional stress
  • Drugs (aspirin)
  • Heartburn

Symptoms And Signs

 Asthma is characterized by narrowing of the airway tubes, with increased secretion of mucus inside the tubes.

The symptoms of Asthma are chronic (greater than 2weeks), intermittent. You are more likely to experience worse symptoms at night, if not well managed. The typical symptoms include;

  • Recurrent episodes of wheeze (a musical, high-pitched, whistling sound produced by airflow disturbance).
  • Cough (chronic, usually worse at night or early morning).
  • Chest tightness or soreness.

Other minor symptoms one can experience include;

  • Body itching (eczema).
  • Allergic rhinitis.
  • Vernal conjunctivitis (commonly known as pink eye)

 The severity of these symptoms varies from person to person and at different times for a person. Asthma symptoms may vary from one episode of asthma attack to the next, by being mild during one and severe in another.

Not everyone has all these symptoms together. Some people may go extended periods without having any symptoms. However, this calm state may be interrupted by periodic worsening of their symptoms called Asthma Attacks.[3]

Classification of Asthma According To Severity

According to the 2019 Global Initiative for Asthma report, asthma can be classified according to the severity in the following order:

  • Intermittent (less than 1 day of symptoms in a week or less than 2 nights of symptoms in a month)
  • Mild Persistent (greater than 1 day of symptoms in a week, asthma attacks may affect activity, greater than 2 nights of symptoms in a month)
  • Moderate Persistent (daily attacks affect activity, greater than 1 night of symptoms per week)
  • Severe, Persistent (continuous limited physical activity and frequent nighttime symptoms)

Diagnosis of Asthma

The diagnosis of Asthma is made clinically by a medical doctor (pulmonologist). It is made based on the patient's account of the illness, supportive evidence as provided by investigations, preferably spirometry.

Your doctor will start by interviewing you about symptoms and also physically examine you. Investigations will be done to assess lung function. These investigations include;

  • Spirometry - Assesses the amount of air blown out of the lungs and the velocity
  • Peak Flow – Measures how well the lungs push out air. It is not as precise as spirometry. It is however useful in testing lung function at home and can be used by patients to figure out what makes asthma worse or triggers it
  • Methacholine challenge- Involves triggering narrowing of the airway using the drug methacholine and subsequently measuring lung function using spirometry.
  • Allergy tests- They can be blood or skin tests to assess allergic agents patients are sensitive to.

Management And Treatment

Asthma is a chronic condition and presently has no permanent cure, however, it can be effectively managed for most patients. The goal of management is to obtain and sustain complete control of the condition. There are several medications used in the treatment of Asthma, the doctor will work with you to make an asthma action plan that will outline the treatment and medication to be used. These medications include;

  • Short-acting beta-agonist - These are better known as reliever medications [4]. They help to loosen the constricted muscles around the airways and ease symptoms. Examples include:
  • Inhaled Corticosteroids - These are used to treat Asthma in the long They are also known as controller medication. Examples include:
  • Long-acting beta-agonists - These medications relax the muscle bands that surround the airways
  • Anticholinergics - These also work to resolve the narrowing of the airway.
  • Theophylline - It opens the airways and eases chest tightness
  • Combination Inhaler - This device gives inhaled corticosteroids and a long-acting beta-agonist together to ease asthma
  • Biologics - They are modern drugs used in the treatment of severe, recalcitrant asthma

The treatment options outlined here should be prescribed or administered by a qualified doctor after an adequate evaluation.

Complications of Asthma

Asthma when not controlled can lead to other serious medical conditions and have deleterious effects on the quality of life of people living with Asthma. These complications include;

  • Absenteeism at work or school
  • Fatigue
  • Pneumonia
  • Lung collapse
  • Respiratory failure
  • Psychological stress

Prevention of Asthma And Asthma Attacks

Since the exact cause of asthma is not known, it is difficult to prevent the occurrence of asthma in a population, however, the occurrence of asthma attacks in people already diagnosed with Asthma can be kept under control in different ways. These include;

  • Knowing the triggers and staying away from them
  • Consistent clinic attendance
  • Following the doctor’ instruction on taking asthma medications
  • Keeping track of the condition and knowing the signs of imminent danger
  • Vaccination against conditions like COVID-19, flu, pneumonia, whooping cough.


HealthCabal Note

Asthma is a very common condition that affects both children and adults. It is without a cure but can be effectively managed by the cooperation of both doctor and patient. If adequately managed people living with asthma can maintain a good quality of life.


References :

  1. WHO - Asthma[1]
  2. WHO - Asthma fact sheet[2]
  3. Davidson principles and practice of Medicine 21st edition- Causes and Risk Factors of Asthma[3]

Further Reading: