What is allergic asthma?
Asthma is a chronic (long-term) respiratory disease characterised by respiratory difficulty and inflammation and obstruction (reversible) of the airways.
A change in the bronchi occurs (larynx-trachea-bronchi-lower respiratory airways or lungs); this reversible obstruction or alteration may improve spontaneously or through treatment.
It occurs intermittently, in the form of asthma attacks. It may lead to a limitation in daily activities; in children in may affect their ability to feel healthy or pay attention in school.
How do I know if I have asthma?
Your medical specialist may make a diagnosis via your symptoms and the medical history and the tests he/she believes are pertinent.
What are the symptoms?
The characteristic symptoms are:
- wheezing or whistling noises when you breathe
- sensation of suffocation
- pain or tightness in the chest
- secretions or mucosity
- sensation of breathlessness
What is an asthma attack?
An asthma attack is an episode of exacerbation of the disease; i.e., something else may trigger the attack, such as a viral infection, medications, allergens or irritants such as cigarette smoke or the cold. Inflammation is produced with the narrowing of the airways, therefore obstructing the passage of air to the lungs, manifesting in difficulty breathing (sensation of suffocation), accompanied by cough and respiratory noises.
Between one attack and the next, the asthma patient tends to remain asymptomatic and apparently healthy.
What are the most frequent triggering factors?
Asthma attacks can be triggered by several factors: viral respiratory infections; indoor or outdoor allergens, such as dust mites, cockroaches, feathers, hair, animal dander or seasonal pollen; irritants such as cigarette smoke, smells or industrial smoke; climate changes; physical exercise; some foods and additives; drugs (ASA or aspirin, certain anti-inflammatory drugs), intense emotions; or gastroesophageal reflux, which may cause bronchoconstriction, thus starting an asthma attack.
The allergens that cause most respiratory allergies are called airborne allergens: many plant pollens, dust mites (small arthropods found on mattresses, sofas and rugs in our houses), epitheliums and domestic animal dander (cats, dogs, rodents, horses, etc.), cockroach excrement and a series of industrial products from the professional sector (bakery, hairdresser, carpentry, chemical industries, etc.).
The pollens that cause most allergies worldwide are grass pollens. In Spain, Parietaria and olive pollen and are also important. Most allergenic plants pollinate in spring.
Does allergic asthma occur in episodes?
Asthma is characterised by a variable and reversible obstruction of the airways, with inflammation and bronchial hyperreactivity.
Attacks are characterised by contractions of the bronchi, oedemas and excess of mucosity, all contributing to the obstruction of the entrance of air from the outside.
What types of asthma are there?
Asthma differs according to the cause:
- Atopic, extrinsic or allergic asthma: secondary to dust mites, pollens, animal epithelia, fungi and foods. It is the most common type.
- Intrinsic asthma: of an unknown cause.
- Professional asthma: flours, industrial products, hair dyes, farmyard caretakers, birds, and others.
- Asthma due to medicinal products: aspirin, anti-inflammatory drugs, etc.
- Exercise-induced asthma.
Is it hereditary?
There is a genetic predisposition to asthma; i.e., if one parent is asthmatic the probability of developing asthma is 25%; and if both parents are asthmatic the probability of developing asthma increases to 70%.
The incidence of asthma in the general population is approximately 10%. It tends to start in childhood or adolescence; half of the cases resolve during puberty and adulthood. The other half continues throughout adulthood or reappears after some years. Between 30% and 50% of asthmatics suffer from allergic rhinitis.
How is asthma diagnosed?
Asthma is diagnosed using respiratory function tests that determine the level of air obstruction.
- Expiratory function tests.
- Measure of peak expiratory flow (peak-flow): used for self-control.
- Bronchodilation test.
- Bronchial provocation test.
- Inflammation markers in secretions and serum.
- Skin tests.
- Determination of IgE – specific to the allergen in blood.
How is it treated?
1. Environmental control
The first step of treatment is to avoid contact with the substances that cause the asthma attack. Avoiding contact with the allergens contributes to better results of the treatment prescribed by the specialist and a decrease in symptoms.
They are used to relieve the symptoms produced by asthma attacks. They are called symptomatic medications and include corticosteroids, beta-adrenergic bronchodilators, leukotriene antagonists and theophyllines
These medications relieve symptoms but do not make the cause of the disease disappear.
- Chronic use medications:
They are used to reduce the inflammation of the mucosa and avoid asthma attacks.
- Inhaled corticosteroids. First-line treatment.
- Chromones. Chromoglicate, has an milder anti-inflammatory effect than corticosteroids.
- Leukotriene antagonists are another alternative.
- Medications used for exacerbations:
They are used occasionally, in short cycles when there is an attack.
- Immediate-action and prolonged-action beta-adrenergic bronchodilators.
- Inhaled and oral corticosteroids.
Commonly known as anti-allergy vaccines, it consists in progressively injecting repeat doses of the allergen in the patient with an aim to reduce or eliminate their sensitivity to the allergen, avoiding or reducing subsequent asthmatic reactions.
The duration of treatment is from 3 to 5 years in most cases.
Immunotherapy is used to treat cases of allergic asthma caused by sensitisation to pollen, dust mites, animal epithelia or certain fungi. In addition to relieving the allergy symptoms, the amount of medication taken is also reduced with this treatment.
It is the only treatment according to the World Health Organization that can modify the natural course of the disease, as it is treating the cause of the disease and not only the symptoms.
It is broadly and scientifically documented that immunotherapy can prevent the development of asthma in patients with allergic rhinitis and a high probability of developing asthma.