Asthma (pronounced AZ-muh) is defined in Essential Allergy, by Niels Mygind, Ronald Dahl, Soren Pedersen and Kristian Thestrup-Pedersen 2nd edition as :
A lung disease characterised by: 1, variable and reversible airway obstruction; 2, airway inflammation; and 3, bronchial hyper-responsiveness.
Asthma is a chronic inflammatory disease that makes airways (bronchial tubes) particularly sensitive to irritants, and this is characterized by difficulty in breathing.
Asthma is a highly ranked chronic health condition in adults in most western countries, and it is the leading chronic illness of children.
Asthma cannot be cured, but for most patients it can be controlled so that they have only minimal and infrequent symptoms and they can live an active life.
If you have asthma, managing it is an important part of your life. Controlling your asthma means staying away from things that bother your airways and taking medicines as directed by your doctor. By controlling your asthma every day, you can prevent serious symptoms and take part in all normal activities. If your asthma is not well controlled, you are likely to have symptoms that can make you miss school or work and keep you from doing things you enjoy.
People with asthma have extra sensitive or hyper-responsive airways.
When a person experiences a worsening of their asthma symptoms, it is called an asthma episode or, in severe cases, an asthma attack. During an asthma attack, smooth muscles around the bronchial tubes contract, making the airway openings narrower so less air can flow through. Inflammation increases and the airways become more swollen and narrow. Cells in the airways also make more mucus than usual, which narrows the airways further. The changes to the airways cause the symptoms of asthma. For example, it is difficult for air to pass in and out of the lungs and the oxygen levels in the blood decrease.
Asthma attacks are not all the same-some are worse than others. In a severe asthma attack, the airways can close so much that not enough oxygen gets to vital organs. This condition is a medical emergency. People can die from severe asthma attacks. A person suffering from an asthma attack has a sensation similar to drowning.
If you have asthma, you should see your doctor regularly. You will need to learn what things cause your asthma symptoms to worsen and how to avoid them. Your doctor will also prescribe medicines to keep your asthma under control.
This narrowing of the air passages is due to different combinations of :
- contraction of muscles around the air passages,
- swelling of the airway lining due to airway inflammation, and,
- excessive mucus in the airways.
About one in 13 adults and one in eight children have asthma in the western world, and rates are on the increase. It can affect anyone, at any age, anywhere.
Asthma is becoming increasingly common in the developed world and is now the most common chronic condition in the west. Aspects of our modern environment such as air pollution, processed foods, and centrally heated, double-glazed houses (an ideal breeding grounds for house dust mites) are thought to be major contributing factors.
An asthma 'attack' describes the symptoms of tightness in the chest, a wheezing or whistling noise in the chest, coughing, breathlessness, and difficulty breathing that occur when the airways become narrowed, inflamed, and blocked by mucus.
An asthma attack can occur suddenly. However, many people with asthma learn to recognise the warning signs that herald an attack, such as an itchy nose or itchy skin, dizziness or light-headedness, or an irritating cough.
Learning the warning signs can often alert a sufferer in time to take preventive action, such as medication.
Asthma is a chronic condition, which means that attacks can occur over a long period of time. Although there are times when acute episodes strike asthmatics, most asthma sufferers say that there are long periods during which they suffer few, if any, symptoms.
Asthma changes progressively during the lifetime of someone who has it. For example, children may grow out of asthma, but some of these people develop asthma again later in life.
Drugs, such as those resembling two of our hormones, help asthma. These two hormones are adrenaline (epinephrine in the USA) and hydrocortisone (a steroid).
There are also other drugs which help treat asthma. Whilst drugs can remove all your symptoms if you have mild asthma, people with more severe or long-standing asthma don't get nearly such good results, so alternate medications are required.
In people who have lifelong asthma, the effectiveness of drugs in removing the obstruction of the airways decreases. One of the aims of treatment, according to current concepts, is to minimise the inflammation in the lung airways which we believe causes this long-term decline.