Allergic Asthma - Cause, Symptoms, Treatment and Prevention

Introduction:

The respiratory tract or the airway is an area contained by the organs of the respiratory system that allow airflow during ventilation. The airway can be subdivided into the upper and lower airway and is lined with a thin tissue called the epithelium.

Asthma is a chronic disorder of the airways characterized by inflammation and narrowing of air passages. Asthma is a very common illness in childhood. The two main types of asthma are allergic asthma and non-allergic asthma.

What Is Allergic Asthma?

Allergic asthma is the reaction induced by a hyperimmune response to inhalation of a specific allergen. It is also known as extrinsic asthma. Allergic asthma is associated with a chronic inflammation that increases airway hyper-responsiveness. Allergic asthma comes under the category of Type I hypersensitivity reaction of the body.

The condition is characterized by obstruction of the airway and reduced expiratory airflow. In addition, there is an overproduction of mucus. About 90 percent of children and 50 percent of adults have asthma symptoms because of allergies.

What Causes Allergic Asthma?

Allergic asthma can be caused by various environmental and medical predisposing factors.

The two main causes of allergic asthma are,

• Allergens:

Allergens are substances that cause allergic reactions and are considered the strongest predisposing factor for asthma. When the allergens are inhaled, the body recognizes them to be harmful and starts releasing immunoglobulin E (IgE) antibodies to fight against them. Continued release of IgE can trigger inflammation of the airways in the lungs. Some of the allergens are pollen, mold, dust mites, and excretes from pets.

• Irritants:

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Irritants are airborne substances that aggravate the asthma symptoms already induced by allergens. Some of the irritants are air pollution, smoke from a fire, candles, incense, or tobacco, perfumes, soaps, talcum powders, fumes from air fresheners or liquidators, closed duty rooms, and chill air.

Some other theories suggesting the development of allergic asthma are,

• Genetics:

Allergies are inherited and run in families. Though the inheritance pattern is unknown, it is estimated that 90 percent of children have allergic asthma risk hereditarily transmitted from their family members.

• Hygiene Hypothesis:

There is an evolving theory suggesting the hygiene hypothesis to be one of the reasons for allergic asthma. This is because children brought up in an abnormally clean environment have limited exposure to allergens and irritants, causing immune intolerance and have a higher incidence of developing allergic asthma in the future.

What Are the Symptoms of Allergic Asthma?

Typical symptoms of allergic asthma include,

• Recurrent episodes of wheezing.

• Runny nose.

• Nasal congestion.

• Chest tightness.

• Breathlessness.

• Cough, especially while talking and at night.

• As the exacerbation continues, it may lead to a decrease in blood oxygen level and a faster heartbeat.

How to Diagnose Allergic Asthma?

• Patient History:

The history of the patient should be evaluated to check for familial predisposition, triggering factors, frequency, duration, and the severity of the symptoms.

• Blood Test:

Physicians may recommend taking a blood test to measure the amount of allergy-specific antibodies (IgE) and eosinophils (a white blood cell that indicates an allergic reaction in the body).

• Skin Prick Test:

It is one of the most effective diagnostic tests to detect allergic reactions. The skin may be pricked with a tiny amount of allergen and checked for the signs of allergic reactions (a raised, itchy red bump at the area of the prick) after 15 minutes. The test identifies allergies to pollen, mold, dust mites, and food.

• Patch Test:

A patch applied with an allergen may be left on the skin of the patients for 48 hours and then checked for allergic reactions.

How to Prevent Allergic Asthma?

One can prevent allergic asthma by avoiding allergens and irritants. The first step is to know the things that trigger the asthma symptoms and learn to limit exposure to them. Some of the methods recommended are,

• Avoid going out during pollen season or wear a mask.

• Keep the indoor space well ventilated with the air flowing in and out.

• Carpets, mattresses, window screens, and curtains must be vacuum cleaned to avoid dust mites.

• Keep the surroundings damp-free and dry, especially in the bathroom and kitchen cabinets.

• Check for pet allergies and find solutions to keep away from them.

• Some allergies are induced in the workplace. Persons whose occupations are associated with chemicals, cotton mills, flour mills, woodcutting, etc., are more prone to develop allergic asthma.

How to Treat Allergic Asthma?

Successful implementation of specific environmental measures can reduce allergy-induced airway inflammation and asthma symptoms and decrease the need for medical therapy. Based on the episodes, severity, and the frequency, the treatment can be planned as follows:

• Tablets: Histamines are chemicals found in the body that cause allergic symptoms. Antihistamine tablets are used to control the symptoms of allergic asthma.

• Sprays and Inhalers: Nasal sprays and oral inhalers with anti-allergic medicines are effective choices since they act locally and have fewer systemic adverse effects. The response is also faster. The medications include steroids (man-made hormones to control inflammation) and bronchodilators (relax the muscles in the lungs and widen the airways to improve breathing).

• Immunotherapy: Specific allergen immunotherapy is a unique therapy to desensitize the body to a particular allergen. Treatment involves injecting the specific allergen in the desired quantity over a period of time. This therapy has the potential to cure allergy symptoms and prevent the development of new allergies. However, research has concluded that allergen immunotherapy has increased the risk for systemic and local adverse effects, and further data is required in relation to long-term effectiveness and secondary outcomes.

• Anti-immunoglobulin E (IgE) therapy: Immunoglobulin E is the antibody responsible for the release of chemicals to induce an inflammatory response in the body. Certain medications interfere with the action of immunoglobulin E and help prevent the allergic reaction that causes asthma symptoms.

Conclusion:

Asthma is the most common chronic disease seen in children. The prevalence of the condition has been increasing over the past decades in developed countries. Asthma has a strong link to allergies. The patients should be educated about allergic asthma concerning the use of medication and encouraged to use an allergy reduction plan. Utmost importance should be given to the treatment of allergy-associated asthma.