What is early versus late stage in asthma?
Doctors have discovered that there may, in fact, be two types of asthma. They are often referred to as early stage and late stage.
Many asthma sufferers who inhale an allergen do not begin to sneeze or wheeze immediately but do so later, after several hours. Once the wheezing begins, it can last several days. This reaction is characteristic of late-stage asthma.
Symptoms of early and late stage asthma
Normally on inhalation of allergens, the airway narrows and wheezing develops within minutes as the lungs swell and passageways narrow. The wheezing will start in about 10 minutes, peak in 30 minutes and resolve in one to three hours. This is the more typical, early asthma response.
But researchers now feel that about 40 percent of asthma attacks develop differently. After inhalation of an allergen, wheezing develops three or four hours later, peaks in four to eight hours and may last 24 hours or longer. Late-onset asthma produces heavy inflammation of bronchial tubes and is the dominant cause of chronic asthma.
Differences in treatment
Discovering these two types of asthma reactions has caused doctors to modify their treatment plans. Drug companies as well are focusing on finding different molecules to address the different reactions.
Bronchodilating drugs such as beta agonists (Allbuterol/Salbutamol, Proventil, Ventolin) and theophylline (Theodur, QTSR) work by opening up the bronchial tubes. They may relieve the symptoms of the early response, but they have little effect on late stage.
The non-bronchodilating or anti-inflammatory drugs such as cromolyn (Intal) and cortisone do not relieve symptoms once they occur but do prevent the late-phase response. All patients with chronic asthma require anti-inflammatory drugs to control their response to allergens.
Source: Mayo Clinic, Heal Asthma