Types of Asthma: Extrinsic and Intrinsic

Types of Asthma

Asthma is a growing worldwide problem. Asthma is classified in various ways. Traditionally, doctors have categorised asthma into two general groups, Extrinsic (allergic) asthma and Intrinsic (non-allergic) asthma, depending upon the types of stimuli that flare up these attacks.

Extrinsic (allergic) asthma:

More prevalent in the younger age group, extrinsic asthma is caused by the immune system’s response to inhaled allergens such as pollen, animal dander or dust mite particles. People with allergic asthma frequently have other allergy-related problems such as hay fever, rhinitis, skin rashes, eczema.

Extrinsic asthma responds quite well to the use of inhaled steroids as these suppress the immune system.
Intrinsic (non-allergic) asthma–

Intrinsic asthma is caused by anything except an allergy. It may be caused by an infection, stress, laughter, exercise, cold air, food preservatives or a host of other factors.

Treatment of intrinsic asthma is not easy as it may not be known what triggers the asthma in the first place and therefore avoiding triggers can be impossible.

Mixed asthma –

As the name suggests, mixed asthma is a mixture of intrinsic and extrinsic asthma. Not only do people react to some allergies but their asthma is also triggered by other factors.

It is common for someone with an extrinsic form of asthma to experience attacks when he has a chest infection – an intrinsic trigger.

Other types of asthma include:

Childhood asthma –

This form of asthma occurs as a child, and most of the time, you outgrow it on growing up. This happens because body goes through a number of functional/hormonal changes while growing up. The treatment of childhood asthma is quite similar to adult asthma as the cause is no different.

Adult-onset asthma –

Adult-onset asthma usually develops after the age of 20, and it affects more women than men. Allergens play a significant role in adults becoming asthmatic. Asthma can actually start at any age and in a wide variety of situations. Another major cause of adult asthma is exposure at work to animal products, plastic, pollution, mites, wood dust, or metals.

Bronchial asthma –

Bronchial asthma is an allergic reaction associated with extreme breathing difficulties and wheezing. The muscles wrapped around the airways, become narrow and spasm. Thick mucus is usually produced in large quantities and the airways become irritated. Most of the attacks are triggered by hyper-sensitivity to air-borne particles(dust, pollen) or any sort of allergy to foods.

Seasonal Asthma –

Seasonal asthma can be triggered by trees, fruits, seeds, grasses or flowers releasing pollen in the air or during any particular climate. For example, some people may have their asthma aggravated during the cold winter season, while others find spring is particularly bad with the increase in flowering plants and air pollen.

Silent Asthma –

Such asthma attacks give very little or no prior warning. They are usually severe and can be even life-threatening.

Nocturnal Asthma

This type of asthma induces wheezing only at night, especially in the wee hours of morning. It is triggered by allergens in home such as dust and pet hair or is caused by sinus conditions. The patient may have wheezing or short breath when lying down or may not notice these symptoms until awoken by them in the middle of the night, usually between 2 and 4am .

A useful treatment in this case is to take a steroid inhaler before going to bed. This reduces the tendency of the airways to narrow. Another measure is to wash bed linen regularly to kill dust mites that cause irritation.

This type of asthma is more difficult to recognize as there are no daytime symptoms, and usually delay proper treatment.

Sports asthma/Exercise-induced asthma –

Shortness of breath and coughing occurring after an exhausting exercise is termed exercise-induced asthma. This is believed to be a reaction to changes in temperature of air in the lung. This phenomenon happens in up to 80% of people with recognized asthma.

Exercise-induced asthma involves symptoms that usually occur about 5-20 minutes after beginning an exercise that involves breathing through the mouth. Sport activities that require continuous strenuous activity or that are played in cold weather are very dangerous and the most likely to trigger an asthma attack.

Precautions include using a bronchodilator inhaler just prior to the sports activity and deep nasal breathing until the body feels warmed up.

Cough variant asthma –

Coughing can occur alone, without the other symptoms of asthma that are usually present. Cough variant asthma causes great difficulty for the doctor to accurately diagnose the true underlying cause of asthma because it can be easily confused with other conditions, such as bronchitis or hay fever or sinusitis. Coughing can occur anytime – day or night.

Occupational asthma –

Occupational asthma occurs due to a trigger in the place of work. Common triggers include pollutants in the air, such as smoke, chemicals, fumes, dust, or other particles; respiratory diseases, such as colds and flu; allergens in the air, such as molds, animal hair, bird feathers, and pollen; extremes of temperature or humidity; and emotional changes.

Most of the trigger substances are very commonly found, and are not normally hazardous. In most people with occupational asthma, the symptoms appear a short time after initiating work and disappear after abandoning the job premises.

Allergy asthma –

This type of asthma is synonymous with a running and blotchy nose, itchy eyes, sneezing, and coughing. Steroid inhalers are used in this condition which soothe the air passages. The best preventive method is to avoid the triggering substances. Allergy desensitization treatment is also a possible option which works by gradually exposing the body to minute amounts of the allergic substance and working up to normal amounts without causing a reaction.

Steroid-resistant asthma –

While most of patients respond to regular steroid therapy, particularly inhaled glucocorticoids (GCs), some are steroid resistant. Glucocorticoids act in asthma by reducing airway inflammation and immune activation. However, patients with steroid resistant asthma have higher levels of immune activation in their airways.