Adrenaline
Adrenaline (or epinephrine) is a hormone produced by the kidneys in response to an emergency situation anaphylaxis . Adrenaline makes the heart beat faster, narrows the blood vessels and dilates the airways.

Airflow limitation 
A prolonged forced expiratory time (ie, longer than 4 seconds). "Airflow limitation" is preferred to other phrases such as "airway obstruction" and "airway narrowing" that imply specific mechanisms of airflow limitation. "Airflow limitation" reflects the heterogeneity of the mechanisms involved in the physiological abnormalities of asthma.

Airway reactivity
(Also called airway hyperresponsiveness.) The airways of a person with asthma are very sensitive and are more likely to constrict after exposure to irritants or triggers.

Airways 
Hollow tubes to and within the lungs through which air passes during breathing. Airways include the trachea, bronchi, and bronchioles.

Allergen 
A protein molecule (antigen) that can trigger the immune system to produce antibodies and thereby cause an allergic reaction. Examples are proteins in pollen, house dust mites and animal dander (dead skin cells). Can also be called "hypersensitivity reaction". Allergies can be triggered by eating, touching, or breathing in an allergen. Allergies are often associated with asthma, especially in children.

Allergy  
This is when the body's immune response reacts in a way which is abnormal. It does this in response to tiny particles of something you come into contact with. The substance is called the allergen. There are many know allergens. Examples include pollen, dust and mould spores.

Alveoli 
The millions of tiny compartments within the lungs at the ends of the airways. (To imagine the shape, picture bunches of hollow grapes at the ends of hollow stems.) Also called "air sacs." Alveoli are where gas exchange takes place-that is, where the blood picks up oxygen (from the air a person has breathed in) and releases carbon dioxide (to be breathed out). (singular: alveolus).

Anaphylaxis
Also known as anaphylactic shock. An acute allergic reaction. Symptoms occur immediately after exposure to an allergen (e.g. insect stings) and include diarrhoea, bleeding, vomiting, bronchospasm and breathing problems. If you experience these or similar symptoms, seek immediate medical assistance, because anaphylaxis can cause loss of consciousness and even death. Anaphylactic reactions can be reversed with adrenaline. If you have already experienced an anaphylactic shock, consider starting specific allergy vaccination and always carry a device containing adrenaline (e.g EpiPen).

Anti-inflammatory  
Inhibiting one or more of the components of the inflammatory reaction.

Antibody 
A protein (also called an immunoglobulin) that is manufactured by lymphocytes (a type of white blood cell) to neutralize an antigen or foreign protein. Bacteria, viruses and other microorganisms commonly contain many antigens, as do pollens, dust mites, molds, foods, and other substances. Although many types of antibodies are protective, inappropriate or excessive formation of antibodies may lead to illness. When the body forms a type of antibody called IgE (immunoglobulin E), allergic rhinitis, asthma or eczema may result when the patient is again exposed to the substance which caused IgE antibody formation (allergen).

Antigen 
A substance that can trigger an immune response, resulting in production of an antibody as part of the body's defense against infection and disease. Many antigens are foreign proteins (those not found naturally in the body). An allergen is a special type of antigen which causes an IgE antibody response.

Antihistamine drugs
Histamine is released by mast cells in body tissue as a response to an allergen and gives rise to the symptoms of an allergic response. Antihistamine drugs influence (reduce) the release of histamine. Antihistamine drugs come in various forms (liquid or powder for the nose, eye drops or tablets) and can provide instant relief from the symptoms, depending on the severity of the attack.

Asprin-sensitive 
A type of asthma in which taking aspirin or NSAIDs triggers asthma symptoms. This particular kind of asthma usually starts in adulthood and is often accompanied by polyps (benign growths) in the nose and/or a chronically runny/stuffy nose (rhinitis). Aspirin-sensitive asthma may respond particularly well to leukotriene-modifying drugs.

Asthma
Asthma is a chronic condition with two main components: constriction—the tightening of the muscles around the airways, and inflammation—the swelling and irritation of the airways. Both the constriction and the inflammation cause narrowing of the airways, which may result in asthma symptoms such as wheezing, chest tightness, or shortness of breath. Asthma can be either allergic or non-allergic.

Asthma action plan 
A list of specific instructions drawn up by a health care professional for a person with asthma to follow at home. An asthma action plan includes a normal schedule for asthma medicines, as well as what to do if peak flow readings or asthma symptoms become worse than usual. Asthma action plans are usually split into Zones: Green Zone, Yellow Zone, and Red Zone.

Asthma management 
A comprehensive approach to achieving and maintaining control of asthma. It includes patient education to develop a partnership in management, assessing and monitoring severity, avoiding or controlling asthma triggers, establishing plans for medication and management of exacerbations, and regular follow-up care.

Asthma specialist 
Health care professional who has received specific training in the diagnosis and management of asthma.

Asthmatic attack
Refers to times when symptoms of asthma such as wheezing, chest tightness, or shortness of breath become more severe, more frequent, or both. They are also called asthma flare-ups or asthma episodes.

Atopy 
This is the tendency to develop an allergy. It does not necessarily mean you will develop the allergy, but if you are atopic you have the tendency to do so. Allergic conditions include eczema and hay fever as well as asthma.

Breathlessness 
This is one of the main symptoms of asthma. It can feel very frightening as you cannot get all the air you need. Different people describe in in different ways, such as 'gasping for breath', 'feeling suffocated' or 'feeling strangled'.

Brittle asthma 
This is a rare form of asthma where people get little or no warning of an asthma attack. They can go from being perfectly well to having a severe life-threatening attack in the space of a few minutes.

Bronchi
The airways that lead from the trachea to each lung, and then subdivide into smaller and smaller branches. They connect to the bronchioles. The walls of the bronchi are made of smooth lining tissue (called endothelium) over fibrous connective tissue, cartilage, and smooth muscle. They also have many glands to produce mucus. (singular: bronchus).

Bronchiole - The tiny (all less than 1 millimeter in diameter), branching airways that lead from the bronchi to the alveoli. Bronchioles have elastic fibers and smooth muscle but (unlike bronchi) no cartilage. Most bronchioles also produce mucus.

Bronchiolitis This is a chest infection which is caused by a virus and occurs in babies. It can leave the baby coughing and wheezing for many months or even years following the infection. It can sometimes be mistaken for asthma. It can also trigger the first episode of asthma.

Bronchitis
Inflamation in the bronchi, resulting in coughing and the production of sputum. Can be caused either by an infection or an allergy.

Bronchoconstriction - The reduction in the diameter of the bronchi, usually because of squeezing of the smooth muscle in the walls. This reduces the space for air to go through and can make breathing difficult.

Bronchodilator - A medicine that relaxes the smooth muscles of the airways. This allows the airway to open up (to dilate) since the muscles are not squeezing it shut. Bronchodilator medicines do not help inflammation, however.

Cardiac asthma This term is now rarely used and is completely different to the asthma we are concerned with here. Cardiac asthma has the same symptoms but these are caused by heart failure and not the changes in the lungs which is the bronchial asthma we are concerned with here.

 

Causal factors 
Risk factors that sensitize the airways and cause the onset of asthma symptoms. The most important of these are allergens and chemical sensitizers.

Causal treatment
A form of treatment which deals with the cause of a disease, not only the symptoms. Specific allergy vaccination is a causal treatment, the use of antihistamines is a symptomatic treatment.

Challenge test
A test done to determine whether or not a person's bronchi are hyperresponsive. The subject breathes in air containing carefully controlled amounts of a substance known to cause bronchoconstriction. (Common substances used include methacholine, histamine, and vaporized salt water.) The bronchi of people with asthma respond to much smaller amounts of the substance than the bronchi of people who do not have asthma. This test is often used to confirm a diagnosis of asthma if there is uncertainty.

Chest tightness  
This is one of the main symptoms of asthma. Chest tightness is often described as a feeling of 'congestion' in the chest or a heaviness. Less commonly it can be felt as chest pain.

Chronic illness
A condition that is long-lasting (e.g., more than 4-6 weeks and in many cases lifelong), which needs to be managed on a long-term basis. Two examples of chronic illnesses are asthma and high blood pressure. Control in the context of asthma is the degree to which a person has been able to reduce daily symptoms and acute episodes of the disease while participating fully in normal activities (such as exercising and sleeping through the night). This is usually achieved through taking medications and avoiding triggers.

Complementary therapy  
These are non-medical treatments which are used alongside conventional medications. They include Yoga, T'ai Chi and Acupressure.

Contributing factors 
Risk factors that either augment the likelihood of asthma developing upon exposure to a risk factor or may even increase susceptibility to asthma. These factors include smoking, viral infections, low birthweight, and environmental pollutants.

 

Controller medications 
Medications taken daily on a long-term basis that are useful in getting persistent asthma under control and in maintaining control. They include anti-inflammatory agents and long-acting bronchodilators. Anti-inflammatory agents, particularly inhaled corticosteroids, are at present the most effective controller medications. Controller medications are also sometimes called prophylactic, preventive, regular preventive, or maintenance medications.

Corticosteroid drugs 
A group of anti-inflammatory drugs similar to the natural corticosteroid hormones produced by the adrenal glands. Among the disorders that often improve with corticosteroid treatment are asthma, allergic rhinitis, eczema and rheumatoid arthritis. In asthma, corticosteroids are often taken through an inhaler for long-term control. They may also be taken orally or given intravenously for a short time if asthma symptoms get out of control.

Cost-of-illness evaluation 
Empiric description of the economic consequences of illness on individuals or populations.

Coughing  
This is one of the main symptoms of asthma. The cough in asthma is the same as the cough you get if you have a cold or chest infection. It can be quite dry or mucus may produced.

Cystic fibrosis  
This is an hereditary condition which results in nutrients from food being poorly absorbed in the gut and too much mucus produced in the lungs.

Diurnal variation  
In the context of asthma, this is the difference between how wide the airways in the lungs are if measured twelve hours apart. Our airways narrow and open naturally over each 24 hour period even in people who do not have asthma. In people with asthma, the variation is much greater. Generally, the greater the diurnal variation, the more unstable the person's asthma. Diurnal variation is usually measured in asthma by taking morning and evening peak flow readings. There are a number of ways of calculating diurnal variation.

DPI
Stands for "dry powder inhaler". This is a variety of device that provides a new way of taking inhaled medicine. The propellants used in regular metered dose inhalers can be bad for the environment. For this reason, drug companies are in the process of switching over to DPI's, which do not use a propellant at all. The medicine is in the form of a very fine powder, which is easily inhaled without the use of an aerosol spray device. There are advantages for patients, too. DPI's can be easier to use, because the patient doesn't have to coordinate the timing of activating the inhaler and breathing in, and the problems of bad taste and unpleasant "feel" are also greatly reduced.

Dust mites  
Very tiny creatures (microscopic, or just barely visible) that live in the dust in people's homes. They are present both in visible dust (under the bed or behind the couch, for example) and in soft places like pillows, mattresses, blankets, and stuffed animals. They thrive especially when the air is humid. Many people are allergic to dust mites, and trying to reduce the number of them in the home is part of many asthma control plans. (For an extremely extensive discussion of dust mites, see the dust mite section.

Economic impact

Effects of a health condition such as asthma measured through direct medical care costs of health services for prevention and treatment; indirect costs in terms of the value of related morbidity, premature mortality, and productivity loss; and intangible costs associated with the value of the psychosocial impacts of a condition.

Eczema
Skin disorder causing reddening, itching, swelling and scaling. Can occur for various reasons, including exposure to allergens.

Edema - Swelling due to collection of fluid (within cells or tissues).

Environmental control 
Removal of risk factors from the environment.

Eosinophil - A type of white blood cell whose major useful role seems to be in protecting against parasitic infections. It is also associated, however, with the inflammation that is at the root of asthma. People with asthma tend to have more eosinophils in their blood and, in addition, have an unusual number of eosinophils "migrate" into their lungs. It is still not entirely clear whether eosinophils cause some of the problems that asthmatics experience, or whether they are just associated with the process without doing damage themselves.

Epinephrine
See adrenaline.

Episode In asthma, a period of markedly worsened symptoms. This may be brought on by exposure to a known trigger or by an upper respiratory infection (a cold), or it may not have a known explanation. An episode may come on all of a sudden or may develop gradually over days. Asthma episodes, at their worst, can be life-threatening, and should always be taken seriously. See exacerbation.

Episodic - Intermittent, with periods of apparent normal function in between periods of symptoms.

Evening peak flow This is your peak flow measured in the evening. If you are monitoring your asthma at home, you would normally take peak flow at about the same time each day (morning and evening) before using any medications for asthma if you need them.

Exacerbate 
To aggravate or make worse. "Exacerbate" is preferred to the words "cause," "precipitate," "induce," and "incite."

Exacerbation 
Any worsening. Onset can be acute and sudden, or gradual over several days. A correlation between symptoms and peak flow is not necessarily found. "Exacerbation" replaces the words "attack" and "episode."

Extrinsic asthma People whose symptoms are brought on by one or more external factors such as pollen or dust, are said to have allergic or extrinsic asthma. This is particularly common in children who develop asthma.

FEF25-75% (Forced Expiratory Flow 25-75%)
This is the average expired flow over the middle half of the FVC manoeuvre and is regarded as a more sensitive measure of small airways narrowing than FEV1. However, it is less reproducible than FEV1 and difficult to interpret when the FVC is reduced.

FEV1
The "forced expiratory volume in one second". In other words, this is the amount of air you are able to blow out in one second of blowing as hard as you can. This measurement, obtained through spirometry gives your doctor an idea of the level of blockage you have in your airways due to inflammation, mucus, or bronchoconstriction. A diagnosis of asthma can be made with confidence when FEV1 increases by 15% or more than 200 mL after bronchodilator use.

FVC 
"Forced vital capacity". This is the total amount of air you can blow out after you've taken a deep breath/maximal inspiration. It is one of the measurements doctors obtain through pulmonary function tests.

GERD
Gastroesophageal reflux disease. GERD is a chronic disorder in which some of the acid and enzymes that belong in the stomach are allowed to get up into the esophagus. This leads to the sensation of "heartburn" and sometimes also an unpleasant sour taste in the mouth. GERD and asthma can make a vicious circle: GERD is more common among people with asthma, and it also seems to make asthma worse in people who have it. Treatment of GERD can lead to an improvement in asthma symptoms.

Guided self-management

Providing patients and their families with suitable information and training so that the patient can keep well and adjust treatment according to a medication plan developed with the health care professional

Health care professional 
Individual who is licensed to care for sick people. Among these: physicians, nurses, nurse-practitioners, physician assistants, therapists, etc.

Histamine
A biologically active substance released from mast cells during an allergic reaction in response to an allergen. Histamine causes running nose, sneezing and itching, and narrows the airways in the lungs. Antihistamines can be used to block the release of histamine that would otherwise occur as a result of exposure to an allergen.

Hives
See urticaria.

Holding chamber  
A device much like a spacer, which is also intended to help medicine from an MDI get into the lungs. The difference between a spacer and a holding chamber is that a holding chamber has a special valve on it that allows a person more time to breathe in the medicine (the breath does not need to be coordinated with the puff). In the real world, holding chambers are often called "spacers" also, even though they are slightly different things.

Hydrocortisone
See corticosteroid drugs.

Hyperreactivity 
Same as hyperresponsiveness, below.

Hyperresponsiveness - The "twitchiness" of the airways of people with asthma, resulting in excessive reaction to substances, smells, and activity. Even little things that would have no effect on the airways of nonasthmatic people cause the smooth muscle of the asthmatic's airway to squeeze and squeeze.

Hyposensitisation
See specific allergy vaccination.

IgE
IgE ( Immune globulin E) is the antibody produced in excess in allergic patients. IgE can be measured in a blood sample to determine if a person is allergic. Allergic people usually have high levels of IgE.

 

Immune system 
A collection of cells and proteins that protects the body from potentially harmful, infectious microorganisms (microscopic life-forms), such as bacteria, viruses and fungi. The immune system plays a role in the control of cancer and other diseases, but also is the culprit in the phenomena of allergies, hypersensitivity and the rejection of transplanted organs, tissues and medical implants. The immune system consists of thymus, bone marrow, lymph nodes and spleen. In allergic people, the immune system overreacts to harmless agents.

Immunoglobulins  
Also known as antibodies. Proteins found in blood and in tissue fluids. Immunoglobulins are produced by cells of the immune system called B-lymphocytes. Their function is to bind to substances in the body that are recognized as foreign antigens (often proteins on the surface of bacteria and viruses). This binding is a crucial event in the destruction of the microorganisms that bear the antigens. Immunoglobulins also play a central role in allergies when they bind to antigens that are not necessarily a threat to health and provoke an inflammatory reaction.

Inflammation
A term that refers to the swelling and irritation in the airways of your lungs. This is the body's response to some kind of injury. It is the body's way of protecting itself and helping it to heal. The purpose of the inflammation is to dilute and destroy the agent causing the inflammation. To do this, the immune system starts a cascade of actions that causes active cells to gather at the affected location. In asthma, the linings of the airways become over-reactive and inflamed. This makes them very sensitive and irritable so that the slightest thing will trigger asthma symptoms. Airway inflammation may always be there, even when you are not having symptoms. There is increasing evidence that, if left untreated, inflammation can damage the airways and cause long-term loss of lung function.

Inhaled corticosteroids (ICS)
A class of medicines used to help treat asthma by reducing inflammation in the airways of the lungs. Because they are inhaled or breathed in, they go directly to the lungs where they are needed and have little effect on other areas of the body (and therefore fewer side effects than corticosteroids taken orally).

Inhaler
A device that delivers medication directly to your lungs, where it’s needed.

Interleukin
Messenger molecule between the different cells of the immune system.

Intolerance
When the body reacts inappropriately but non-allergically (i.e. without IgE production) to a particular substance. Many people experience reactions to certain types of food. Of these, 2-3% are allergic to the foods concerned; the rest experience intolerance.

Intracutan test
Intracutan tests are used to diagnose allergies. A small amount of allergen extract is injected under the skin on your arm. If the area becomes itchy, reddish and swelling you may have an allergy.

Intrinsic asthma 
Asthma that has no apparent external cause. People whose symptoms do not seem to be brought on by anything external are said to have non-allergic or intrinsic asthma. It is more common in people who develop asthma for the first time in adulthood. Symptoms are more likely to be triggered by, for example, exercise, emotion or some drugs such as aspirin. The term "intrinsic asthma" is not used much any more.

Intubation
The process of putting a tube down someone's throat into the trachea; the tube is connected to a machine (a respirator, or ventilator) that pushes measured amounts of air into the lungs (and then lets it out again) to help the person breathe. This can save the life of a person having a severe asthma episode but also has many risks and possible complications.

In vivo
In vivo means 'in the living organism', i.e. examination of the living organism - for example, a skin prick test.

Irritant  
A substance that triggers asthma symptoms by irritating the airway when breathed in. Examples include cigarette smoke, fumes from a harsh cleaning fluid, or strong perfume. (Allergens are a different type of asthma trigger, which cause symptoms through an allergic reaction rather than by irritation.)

Leukotriene
A type of chemical involved in inflammation. Leukotrienes seem to play a particularly important role in the inflammation associated with asthma. Recently some asthma medicines have been developed that work to reduce leukotrienes or their effects (these are called "leukotriene modifiers" or "leukotriene inhibitors").

LRI
Lower respiratory infection. Some examples include pneumonia, bronchitis, and bronchiolitis.

Lymphocyte 
Any of a group of white blood cells of crucial importance to the adaptive part of the body's immune system. The adaptive portion of the immune system mounts a tailor-made defense when dangerous invading organisms penetrate the body's general defenses.

Macrophage
A large cell that acts as a scavenger, helping the immune system to destroy foreign agents.

Mast cell

These cells play an important role in the body's allergic response. Mast cells are present in most body tissues, but are particularly numerous in connective tissue, such as the dermis (innermost layer) of skin, and also are found in the airways. Following subsequent allergen exposure, the mast cells release substances such as histamine (a chemical responsible for allergic symptoms) into the tissue.

 

Medication plan 
A specific plan, preferably written (or pictorial for low-literacy populations), to achieve and maintain control of asthma based on use of controller and reliever medications in a stepwise approach. A medication plan also includes instructions on how to recognize worsening of asthma and what actions to take (this part of the medication plan is often referred to as the "action plan" because it outlines how to start treatment of an exacerbation and when and how to seek medical care).

Metered dose inhaler
Often called "MDI". A device that allows delivery of medicine directly into the lungs. The medicine is in the form of a very, very fine powder, and a propellant is used to get the powder out in a cloud to be inhaled. Unfortunately, the propellant used in the standard MDI's is composed of CFC's (chlorofluorocarbons), which are involved in the destruction of the ozone layer. Different types of devices to deliver medicine to the lungs are now being designed, and some are already available to consumers (see DPI). For instructions on use of MDI's (as well as of the newer devices), go to Correct Use of Inhalers and Nebulizers (currently under construction.)

Methacholine 
A type of chemical used in challenge testing. Everybody's airways respond to it, but the airways of a person with asthma respond much more and at lower doses.

Morbidity and mortality 
Sickness and death. These words are usually used when looking at the effects of a disease in a population. For example, "asthma causes significant morbidity in this group" means "asthma makes a lot of people in this group sick." "Asthma mortality in this country is unacceptable," means "It is unacceptable if anyone in this country dies of asthma."

Morning peak flow  
This is your peak flow measured in the morning. If you are monitoring your asthma at home, you would normally take peak flow at about the same time each day (morning and evening) before using any medications for asthma if you need them.

Mucus 
A substance secreted by various tissues in the body (the mucous membranes) made up of water, mucin (a glycoprotein), salts, and some cells. In the lungs, mucus serves to lubricate the insides of the airways and to trap inhaled foreign particles so that they can be coughed out. In asthma, however, an excess of mucus is produced and can actually block airways. Mucus also tends to be thicker and more viscous in asthmatics.

Patient education 
The aim of patient education is "guided self-management." The health care professional provides the patient and the patient's family with suitable information and training so that the patient can stay well and adjust treatment according to a medication plan developed with the health care professional. Effective patient education involves a partnership between patient and health care professional with frequent revision and reinforcement. Training includes teaching specific asthma management skills such as how to take medicine correctly, how to recognize when asthma gets worse, and what actions to take to achieve and maintain control.

Peak flow meter  
Peak flow is measured using a hand held instrument called a peak flow meter. When you blow down the meter it measures the speed of the air as it passes through the hollow centre of the meter; there is a scale in litres per minute (abbreviated to l/min). This is an indication of how well the lungs and airways are doing. A peak flow meter is an important part of an asthma home-monitoring plan.

PEF (peak expiratory flow) home monitoring 
Measurement of PEF on a regular basis at home with a portable peak flow meter. PEF home monitoring is especially useful in patients over 5 years of age (who have the ability to use the flow meter) with moderate persistent to severe persistent asthma

 

PEF variability 
Diurnal variation in peak flow is expressed by the formula:

Personal best peak flow  
This is your highest peak flow when you are well and your asthma is as well controlled as possible. It is usually measured in the middle of the day after using your immediate reliever medication.

Pollen
Pollen is the male fertilising agent of flowering plants, grasses, trees and weeds. It can act as a trigger for many people with allergies or asthma. Pollens may peak at certain times of the year.

Predicted peak flow  
Studies have been carried out measuring peak flow in people who do not have asthma, of different age, sex and height. These 'predicted peak flow' values are commonly used as a reference point for people who have asthma, to see how close they are to what is considered a 'normal' value i.e. what they would be expected to achieve if they did not have asthma.

Preventer  
This is a medication which prevents asthma symptoms from coming on. It works by reducing the inflammation present in the airways which is responsible for asthma symptoms. Preventers must be used regularly every day for them to work effectively.

Prevention 
Primary prevention is preventing development of the condition of asthma. Secondary prevention is preventing exacerbations of asthma in those who already have the condition and avoiding deterioration in lung function or death from the condition.

Provocation test
Also called a challenge test. A testperformed on eyes, nose or lungs and used to diagnose an allergy or monitor the effect of e.g. specific allergy vaccination. The allergen is introduced in increasing doses to the organ to see if the person reacts and, if so, at what level of exposure.

Red zone Different zones are often used in managing asthma to give people an idea as to how well they are. Most of the time the zone ranges are based on peak flow readings. There are usually three zones which are coloured green, yellow and red going from good to bad in the same order. If your peak flow falls into your red zone it usually means your asthma is very severe and you need to get help. You should not spend any of your time in your Red Zone!

Reliever medications 
Short-acting bronchodilating medications that act quickly to relieve airflow limitation and its accompanying acute symptoms such as cough, chest tightness, and wheezing. It works by relaxing the muscles around the airways to open them up, thereby relieving the symptoms and enabling you to breathe more easily. Relievers are also sometimes called quick relief medicine or rescue medicine.

Residual volume  
The amount of air left in your lungs when you have exhaled as far as you can. (Your body doesn't let you exhale all the air in your lungs, because then your lungs would collapse.) This is one of the measurements obtained in pulmonary function testing.

Respirator 
See intubation.

Rhinitis
Rhinitis is inflammation of the cells lining the nose resulting from the inhalation of an allergen. The symptoms include nasal obstruction, runny nose and sneezing. Rhinitis can be seasonal, e.g. allergy to pollen (hay fever), or all year round - e.g. allergy to animals or dust.

Risk factor  
An agent that when present increases the probability of disorder expression. There are two types of risk factors: 
1. Risk factors involved in the development of the condition of asthma. For example, a risk factor for the onset of asthma can be inherited, such as atopy. Alternatively, a risk factor can be due to environmental exposure. See "causal factors" and "contributing factors." 
2. Risk factors that cause asthma exacerbations in individuals who already have the condition. These are also called triggers (for example, dust; mites; exercise; cold, dry air).

Reversibility test  
This is a test the doctor may carry out to help diagnose whether or not you have asthma. The doctor will measure your peak flow, then give you some reliever medication. When the reliever has had time to work maximally (usually about 20 minutes) s/he will then get you to repeat you peak flow. If the value has increased by 15% or more this may mean asthma.

Severity
How bad or serious a disease is. In asthma, severity is generally broken up into four categories: mild intermittent, mild persistent, moderate persistent, and severe persistent. (Some experts also include a category for "severe intermittent" for those unusual people who most of the time have no asthma symptoms at all but occasionally have very serious or life-threatening asthma episodes.) Just as we do not know what causes asthma, we do not understand why individuals differ so much one from another in asthma severity.

Shots
See specific allergy vaccination.

Sinusitis
An inflammation of the sinuses (hollow spaces in the bone of the cheeks and forehead) due to infection. Common symptoms of sinusitis include pain in the face, colored (not white or clear) secretions from the nose, and headache. A lot of people who have asthma also have problems with recurrent sinusitis. There is some evidence that a flare-up of sinusitis can trigger a worsening of asthma symptoms, but this is still not certain.

Skin prick test
Skin prick tests are used to diagnose allergies. Pricking gently through a drop of allergen extract placed on the surface of the arm may result after 10-15 minutes in the appearance of a small, itchy swelling and a reddening of the skin. This indicates an allergy.

Smooth muscle 
Sometimes called involuntary muscle. A type of muscle found many places in the body, including the walls of the airways. (It is called smooth muscle simply because of how it looks under a microscope, to distinguish it from striated muscle, which is what makes up the heart as well as voluntary (skeletal) muscle.)

Social impact Effects of a health condition on social functioning. In asthma, social impacts include impaired child development and education as well as disruption and loss of adult employment and productivity.

Spacer 
A device usually consisting of a plastic chamber that attaches to a metered dose inhaler on one end, with a mouthpiece on the other end. A spacer is intended to help medicine from a metered dose inhaler get into the lungs. Without a spacer, much of the medicine in an inhaler "puff" gets deposited on the tongue or in the back of the throat. A spacers comes in different shapes and sizes, some with masks and others with mouthpieces. It is particularly suitable for young children and people suffering from an asthma attack. 

Specific allergy vaccination
Specific allergy vaccination is also called specific immunotherapy, hyposensitisation or allergy shot. It is a vaccination programme that affects the natural course of an allergic disease, not only its symptoms. When the patient is given increasing doses of the allergen to which he or she is allergic, the immune system becomes less sensitive and the patient no longer reacts. Two different types of vaccine exist: a depot (slow-release) preparation and an aqueous solution.

Spirometer  
This is an instrument similar to a peak flow meter and is used for pulmonary function test to diagnose asthma in a doctor's office or pulmonary function laboratory. The instrument measures how fast a person can blow out air, and how much air is blown and thus gives additional information compared to a peak flow meter.  The results of this test include the FEV-1, the peak flow, and the FVC.

Stable peak flow  
Your peak flow is stable when your readings remain in your green zone (usually between 80% and 100% of your personal best peak flow), you have no morning dip and your diurnal variation is not greater than 20%.

Status asthmaticus 
A severe episode of asthma that is not helped (or only partially helped) by inhaled bronchodilators, and that threatens a person's ability to breathe altogether. May require intensive bronchodilator therapy, systemic corticosteroids (oral or IV), or even intubation.

Stepwise approach 
The number (type) and frequency of medications are increased with increasing severity of symptoms. The aim is to accomplish the goals of therapy with the least possible medication.

Steroids
A general term for a wide variety of chemicals, natural and synthetic. In the context of asthma, "steroids" is usually a shorthand way of referring to corticosteroid medicines (taken to reduce asthma inflammation). Other steroids, including natural and synthetic sex hormones (such as the testosterone-like compounds sometimes used by athletes to build their muscles), are generally unrelated to asthma. See corticosteroid drugs.

Support group
A group of people all sharing a certain problem or concern (such as having asthma, or having a child with asthma) who meet to discuss how they are dealing with it. Support groups provide emotional support by decreasing a person's sense of isolation and can also provide practical advice, since other members of the group have experience confronting similar challenges. Social workers associated with local hospitals or clinics should have information on what support groups are available in your area.

Symptomatic treatment
A treatment with drugs that only affects the symptoms of the disease, not its cause - e.g. antihistamines and corticosteroids.

Symptoms of asthma
The five main signs and symptoms of asthma are coughing, wheezing, chest tightness, shortness of breath, and mucus production.

Systemic 
Relating to or affecting the body as a whole (rather than one specific organ or part).

Theophylline 
Theophylline is a bronchodilator drug, given by mouth, that widens the airways to the lung.

Thrush Also called candida, this is a fungal infection in the mouth which can be caused by using steroid based inhalers. It is a localised infection and is unusual when low dose inhalers are used. It can be prevented by using a spacer, brushing teeth and rinsing the mouth following inhaler use.

Total lung capacity - The total amount of air in the lungs when a person has breathed in as far as possible. This is one of the measurements obtained in pulmonary function testing.

Trachea 
The largest breathing tube in the body, passing from the throat down to the chest (where it connects to the two bronchi leading to the lungs).

Trigger 
A trigger is anything which brings on or worsens the symptoms of asthma. Most people with asthma have more than one triggers. Different people may have different sets of triggers. Examples of common triggers are pollen, exercise, the common cold and the house dust mite.

T-cell
T-cells or T-lymphocytes (white blood cells) determine together with interleukins which class of antibodies is to be produced by the B-cells.

URI - Upper respiratory infection. Medical term for a "cold".

Urticaria
Urticaria, also called "hives", is an inflamation of the skin - an itchy rash.

Zone system 
An asthma management system based on specified levels of symptoms and PEF that helps patients monitor their disease, identify the earliest possible signs that the day-to-day control of asthma is deteriorating, and act quickly to regain control. Typically, the system mimics a traffic light, with green (all clear), yellow (caution) and red ( DANGER! Get to the emergency room as quickly as possible) zones. A patient management plan based on a zone system describes medications, environmental control measures, and contact with a health care professional for each zone.

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