Extrinsic asthma:

It is the most common form of asthma in all age group and is more prevalent in younger age group. Extrinsic asthma is also known as atopic asthma or allergic asthma. When any foreign particle either an allergen or an antigen enters into the body, the immune system of the body overreacts and forms antibodies and other chemicals to defend the body. This is a natural process of the body. The production of antibodies and the other chemicals bring specific changes in the airways which leads asthma. Various inhaled allergens like pollens, animal dander and dust mites are most common causes to develop extrinsic asthma. People with allergic asthma and their family members frequently have other allergy related problems such as fever, skin rashes, hives, eczema, and rhinitis.

Intrinsic asthma:

The intrinsic asthma is not related with the allergies. In fact it is caused by inhalation of certain chemical such as cigarette smoke, fumes of motor vehicles and factories, strong odors, intake of certain medicines like aspirin; chest infections, stress, laughter, exercise, cold air, food preservatives like azinomoto or a myriad of other factors. Antibodies are not produced by the body and the cause of developing intrinsic asthma may be the irritation of the nerves or muscle in the airway.

Mixed asthma:

It is mixture of allergic asthma and intrinsic asthma. These people react to some allergies but their asthma is also triggered by other things also. For example symptoms are aggravated in an asthmatic while facing the chest infection.

Apart from above classification of asthma you can further categorize asthma. Your condition may have been given one of the following labels.

Cough variant asthma:

Cough may be the sole manifestation of asthma or a distressing symptom. This is particularly important in the case of children. In such cases, the use of anti asthma therapies after investigation will relieve the cough.

Nocturnal asthma:

The patients presents themselves with the symptoms like wheezing, cough, breathlessness in the night in between 2.00am to 4.00am. Such night time symptoms disturb sleep and impair the quality of life. Nocturnal Asthma is defined as an overnight fall of more than 20% in the FEV1 or PEFR. Sometimes this may be the sole manifestation of asthma or an important indicator of poorly controlled day time asthma. This night time propensity is due to a number of reasons:

· Exposure to dust mite, animal dander. · Gastro-esophageal reflux. · Post nasal drip. · Decreased cortisol level. · Increased parasympathetic activity. · Increased level of histamine. · Increased sensitivity to histamine. · The effect of medicines may wear off. · Early morning fall in circulating adrenaline. · Overnight changes in vagal tone. · Airway cooling at night.

Gastro-esophageal asthma:

Worsening of Asthma symptoms after meals or dyspnoea occurring only after meals is due to gastro-esophageal reflux. http://www.asthmahelpline.com