Throughout last years there have tried to develop adapted classifications of the asthma, based on the only provocative factors (allergens, drugs, occupational substances, etc...), in the grade of bronchial reactivity, in the fisiopatología, the therapeutic answer or other elements, but none of them is provided with general acceptance. To practical effects, there have been assumed conventional classifications that turn out to be useful in the clinical categorization of the patients, in accordance with the factors etiológicos more important, the course of the illness and the gravity of the symptoms.

The bronchial asthma not only is characterized by the wide changes in the expression of the illness, but also by the frequency which multiple implied factors meet, in the same patient. In fact, it is slightly probable that only one causal factor is responsible for all the alterations that they accompany to the asthma, although, of course, a concrete agent can be the person in charge of the symptoms in a moment of the evolution.

Since Rackemann introduced in 1918 the asthma terms extrinsically and asthma intrinsically, these they have come using of traditional form, despite all the limitations of this classification.

The Asthma extrinsic includes those patients in whom a reaction antigen - antibody can be demonstrated like desencadenante of the process. In general this reaction antigen - antibody is half-full for IgE (asthma extrinsic atópico), while in other cases generally of occupational origin type cannot demonstrate a hypersensitivity reaction I of Gell and Coombs (asthma extrinsic not atópico).

The Asthma intrinsic is a wider term and one applies to a heterogeneous group of patients with the common characteristic of which it is not possible to detect a concrete antigen as it causes precipitante. The asthma intrinsic has also a series of proper characteristics that separate it from the extrinsic one: It usually begins in the adult life, in many cases one associates with nasal polyps, maxillary sinusitis, and/or idiosyncrasy aspirin and other anti-inflammatory not esteroideos triad A.S.A. or of Vidal, and presents a chronic course with frequent need for oral steroids for his control.

On the other hand, inside a classification etiológica of the bronchial asthma it is necessary to mention certain special forms of asthma.
Asthma induced by exercise. It is a phenomenon that can happen of isolated form or in association with any type of asthma. Many patients experience obstruction of the airlines from 5 until 20 minutes after completing the exercise or during the same one, for a mechanism that seems to include the secondary cooling, the relative dryness of the airline to the increase of the ventilation and the heat loss of the airline.

Occupational asthma. It is produced by the inhalation of industrial smokes, dust and emanations that are in the work place. Four answer bosses have been described in the occupational asthma: Immediate exclusive, late exclusive, dual, and night appellant for several days. These patients, although changing according to the type of answer that they show, they usually improve out of his work place, during the holidays, weekends and fall periods. The recent reviews describe several possible mechanisms patogénicos for the occupational asthma, changing from the simple reaction irritativa in patients with bronchial hyperreactivity (for example, SO2 ó NO2) to the reactions antigen - antibody come up or not by IgE (for example, epitheliums of animals, seeds and some compounds of low molecular weight like isocianatos or resins epoxi).

The Asthma is intermittent or episodic if the illness studies with shortness of breath crisis with more or less asymptomatic intervals.

It is named an Asthma chronically or persistently if the symptoms are more or less permanent and supported with periodic aggravations.

As for the severity of the process in every patient in particular, light asthma is the one that does not interfere with the daily activities and performs simple pharmacological control. Asthma moderated is that that, sometimes, interferes with the normal activities, and sometimes, it needs more aggressive therapies for his control. Serious asthma (severe) is the one that interferes seriously with the daily activities, it implies an exhaustive control and polytherapy, or studies with episodes that put in danger the life (asthmatic status), in all of them one associates objective measurements of bronchial obstruction.

The last international consensuses divide the asthma as his severity in 4 stadiums (GINA, 1998).