What is asthma?
Asthma is a chronic disease that affects the smallest airways of the lungs called bronchioles. Symptoms include wheezing, cough, tightness of the chest and shortness of breath and are caused by contraction of the smooth muscle surrounding the bronchioles, which in turn causes narrowing or constriction of the bronchioles, known as bronchospasm. The underlying cause of asthma is inflammation, which may be triggered by an allergic reaction or a reaction to an irritant; also asthma attack can be triggered by exercise, some medications like aspirin, stress and other emotions.
Chronic obstructive pulmonary disease (COPD) is another respiratory disorder where breathing is impaired, caused by chronic inflammation and damage to the bronchioles.
What is an allergy?
An allergy is the result of an allergic reaction when the immune system reacts to a substance that is not normally harmful. The type of allergic reaction depends on the cause and the allergen, which is the substance that induces an allergic reaction. For example, Asthma can be triggered by an allergy to inhaled pollen, mould, animal fur or house dust mites. These allergens can also trigger allergic rhinitis. Urticaria or hives is an allergic reaction of the skin, often caused by allergy to a medicine, a food, an insect sting or latex gloves.
An allergy can also affect other parts of the body, such as the gastrointestinal system causing stomach pain, diarrhea and vomiting. A severe allergic reaction called anaphylaxis can cause swelling of the throat and tongue, difficulty breathing, drop in blood pressure and can be life-threatening.
Types of asthma medication
Medication available for the treatment of asthma and other chronic breathing disorders fall into three categories:
Inhaled asthma medication
Most asthma medications are taken using an inhaler so that the drug goes directly to its target, the airways of the lungs. Inhaled asthma medications may be delivered as an aerosol with a metered dose inhaler (puffer) using a propellant gas to create an aerosol, or by a nebuliser that creates a fine mist which can be inhaled using a mask or mouthpiece. The medication may also be inhaled as a dry powder using a special device for powder delivery.
Inhalers are used for brochodilators, or reliever medications that are generally for symptom relief or asthma attack; and for anti-inflammatory drugs, which are preventer medications for chronic inflammation of the airways.
Combination inhalers are also available which contain two different drugs in the same inhalation device.
Types of inhaler
Inhaler devices used to deliver medication into the airways are:
- Metered dose inhaler (MDI) that uses a propellant gas to create an aerosol. Most are now CFC-free as these less damaging to the environment.
- Dry powder inhaler, such as the accuhaler, turbuhaler or rotahaler that does not need a propellant.
Oral asthma/allergy medication
Some steroid medication for severe asthma or allergy can be taken orally as tablets to gain control of symptoms. Leukotriene receptor antagonists are also taken orally as tablets.
Types of allergy medication
Allergy medications are known as antihistamines
because they block the action of histamine, a chemical released during an allergic reaction that is responsible for triggering symptoms of allergy. Most antihistamines are taken orally as tablets and are non-sedating. Some antihistamines are sedating because they also act on the central nervous system. Antihistamines can also be taken as eye drops and using a nasal spray.
Nasal sprays for treating allergy
Allergy medications can also be taken as a nasal sprays
. The types of medication available as a nasal spray include antihistamines to treat symptoms of allergy; also corticosteroids that treat symptoms of inflammation of the nasal passages caused by an allergic reaction.