Asthma, a chronic disease, involves the airways in the lung (1). Air enters or leaves the lungs through the airways or bronchial tubes. The lung contains many tiny air passages that deliver oxygen from the air inhaled to the bloodstream in your body. People with asthma will have inflammation in their airways. When any factor triggers the symptoms, the airways will be more swollen, and the muscles around the airways will tighten. Thus, the airflow in and out of the lungs becomes hard, which leads to an asthma attack.

What Causes Asthma?

Is there an exact cause and cure for asthma? No. However, the response of the immune system to substances in the lungs generally causes asthma. Causes may vary for each person; it may result from complicated interactions between a person’s inherited genes and interactions with the environment.

• Environmental factors

• Hormonal factors

• Genetic factors

• Stress

• Hygiene hypothesis

Symptoms of Asthma

Wheezing is the common symptom of asthma; you may sound like whistling or squealing when you breathe. Other symptoms are,

• Tightness in the chest

• Shortness of breath

• Panic or anxiousness

• Fatigue

• Increased mucus production

• Struggling to talk and sleep

• Coughing at night, while laughing and exercising

Symptoms shall vary depending on the type of asthma you experience.

Classification

These classifications can define the severity of asthma, and they help by making diagnosis and treatment easier.

• Intermittent – Many people will have this type of asthma, which doesn’t affect their daily activities. Mild symptoms that last less than 2 days a week or 2 nights a month are shown.

• Mild Persistent – This asthma symptom may appear more than twice a week (not daily) and up to 4 nights a month.

• Moderate Persistent – Slightly affect some daily activities. Symptoms appear daily and at least one night every week, but not every night.

• Severe Persistent – Symptoms occur numerous times daily and most nights. Regular activities are extremely affected.

What are the Types of Asthma?

Among the different asthma types, bronchial asthma is the common one. It affects the bronchi in the lungs. Other types include,

1. Childhood Asthma

It is the same as asthma in adults, but the only difference is the change in symptoms. Childhood asthma is common in children than in adults, and it can occur at any age (2, 3). This asthma may increase for some when they reach adulthood. Also, it will be a lifelong disorder for some children. Some factors causing childhood asthma are,

• Exposure to cold air

• Cold and respiratory infections

• Sudden temperature change

• Allergens and air pollutants

• Excitement

• Exercise

• Stress

• Smoking cigarette

2. Adult Asthma

It develops in adulthood, though initial signs are shown during childhood in most cases (4). Several allergens trigger asthma symptoms in adults (5), which are also called allergic asthma (extrinsic asthma). Common allergens are:

• Dust and mold

• Food

• Pollen

• Some chemicals

• Cigarette smoke

3. Nonallergic Asthma (Intrinsic Asthma)

Air irritants that are not related to allergies, will provoke this asthma (6). These irritants are,

• Viral illness

• Burning wood

• Perfumes and air fresheners

• Household cleaning products

4. Occupational Asthma

This asthma occurs due to the exposure of workplace substances that induce an allergic reaction (7). They are,

• Industrial chemicals

• Rubber latex

• Fumes and gases

• Dust

• Dyes

• Animal proteins

Industrial areas where these irritants exist are,

• Woodworking

• Farming

• Textiles

• Electronics and metalwork

• Hairdressing salons

• Manufacturing

• Indoor swimming pools

5. Exercise-Induced Bronchoconstriction (EIB)

Earlier, it was named as exercise-induced asthma (EIA) (8). It affects people in a few minutes they start doing exercise, and after exercise, it lasts up to 10-15 minutes (9). However, 90% of people with asthma encounter EIB, but not everyone with EIB will have other asthma types.

6. Aspirin Induced Asthma (AIA)

It is also called as aspirin-exacerbated respiratory disease (AERD). Typically, it is severe, and it will be triggered while taking aspirin or other NSAID’s such as ibuprofen (Advil) or naproxen (Aleve) (10). 

People in the age limit of 20 to 50 will experience this asthma. Signs of asthma appear within minutes or hours. These patients usually have nasal polyps, and 9% of people with asthma will have AIA.

7. Nocturnal Asthma

During sleep, asthma is worse, and the reason is unknown. Sometimes sleep will cause changes in bronchial function (11). Explanations for the cause include,

• Cooling of the airways

• Being in a reclining position

• Increased exposure to allergens

• Hormone secretions that follow a circadian pattern

8. Cough-Variant Asthma (CVA)

CVA does not show usual asthma symptoms such as wheezing and shortness of breath. It is identified by a persistent, dry cough (12). If left untreated, it prompts full-blown asthma flares with other common symptoms.

Risk Factors

People with higher risk include, 

• Pregnancy

• Obesity

• Family history of allergic conditions

• Smoking tobacco & cigarette

• People with allergic rhinitis

Summary

Asthma is the response of the immune system to substances in the lungs. Wheezing is a common asthma symptom. There is no exact cause and cure for asthma. Classification of asthma helps to define its severity, which makes the diagnosis and treatment easier.