Medical Disease: Types of Asthma

Child-Onset Asthma

Asthma that begins during childhood is called child-onset asthma. This type of asthma happens because a child becomes sensitized to common allergens in the environment - most likely due to genetic reasons. The child is atopic - a genetically determined state of hypersensitivity to environmental allergens.

Allergens are any substances that the body will treat as a foreign body, triggering an immune response. These vary widely between individuals and often include animal proteins, fungi, pollen, house-dust mites and some kind of dust. The airway cells are sensitive to particular materials making an asthmatic response more likely if the child is exposed to a certain amount of an allergen.

Adult-Onset Asthma

This term is used when a person develops asthma after reaching 20 years of age. Adult-onset asthma affects women more than men, and it is also much less common than child-onset asthma.

It can also be triggered by some allergic material or an allergy. It is estimated that up to perhaps 50% of adult-onset asthmas are linked to allergies. However, a substantial proportion of adult-onset asthma does not seem to be triggered by exposure to allergen(s); this is called non-allergic adult-onset asthma. This non-allergic type of adult onset asthma is also known as intrinsic asthma. Exposure to a particle or chemical in certain plastics, metals, medications, or wood dust can also be a cause of adult-onset asthma.

Exercise-Induced Asthma

If you cough, wheeze or feel out of breath during or after exercise, you could be suffering from exercise-induced asthma. Obviously, your level of fitness is also a factor - a person who is unfit and runs fast for ten minutes is going to be out of breath. However, if your coughing, wheezing or panting does not make sense, this could be an indication of exercise-induced asthma.

As with other types of asthma, a person with exercise-induced asthma will experience difficulty in getting air in and out of the lungs because of inflammation of the bronchial tubes (airways) and extra mucus.

Some people only experience asthma symptoms during physical exertion. The good news is that with proper treatment, a person who suffers from exercise-induced asthma does not have to limit his/her athletic goals. With proper asthma management, one can exercise as much as desired. Mark Spitz won nine swimming gold medals during the 1972 Olympics and he suffered from exercise-induced asthma.

Eighty percent of people with other types of asthma may have symptoms during exercise, but many people with exercise-induced asthma never have symptoms while they are not physically exerting themselves.

Cough-Induced Asthma

Cough-induced asthma is one of the most difficult asthmas to diagnose. The doctor has to eliminate other possibilities, such as chronic bronchitis, post nasal drip due to hay fever, or sinus disease. In this case the coughing can occur alone, without other asthma-type symptoms being present. The coughing can happen at any time of day or night. If it happens at night it can disrupt sleep.

Occupational Asthma

This type of asthma is triggered by something in the patient's place of work. Factors such as chemicals, vapors, gases, smoke, dust, fumes, or other particles can trigger asthma. It can also be caused by a virus (flu), molds, animal products, pollen, humidity and temperature. Another trigger may be stress. Occupational asthma tends to occur soon after the patients starts a new job and disappears not long after leaving that job.

Nocturnal Asthma

Nocturnal asthma occurs between midnight and 8 AM. It is triggered by allergens in the home such as dust and pet dander or is caused by sinus conditions. Nocturnal or nighttime asthma may occur without any daytime symptoms recognized by the patient. The patient may have wheezing or short breath when lying down and may not notice these symptoms until awoken by them in the middle of the night - usually between 2 and 4 AM.

Nocturnal asthma may occur only once in a while or frequently during the week. Nighttime symptoms may also be a common problem in those with daytime asthma as well. However, when there are no daytime symptoms to suggest asthma is an underlying cause of the nighttime cough, this type of asthma will be more difficult to recognize - usually delaying proper therapy. The causes of this phenomenon are unknown, although many possibilities are under investigation.

Steroid-Resistant Asthma (Severe Asthma)

While the majority of patients respond to regular inhaled glucocorticoid (steroid) therapy, some are steroid resistant. Airway inflammation and immune activation play an important role in chronic asthma. Current guidelines of asthma therapy have therefore focused on the use of anti-inflammatory therapy, particularly inhaled glucocorticoids (GCs). By reducing airway inflammation and immune activation, glucocorticoids are used to treat asthma. However, patients with steroid resistant asthma have higher levels of immune activation in their airways than do patients with steroid sensitive (SS) asthma.

Furthermore, glucocorticoids do not reduce the eosinophilia (high concentration of eosinophil granulocytes in the blood) or T cell activation found in steroid resistant asthmatics. This persistent immune activation is associated with high levels of the immune system molecules IL-2 (interleukin 2), IL-4 and IL-5 in the airways of these patients.