Asthma- intermittent narrowing of the bronchi

A lung disease in which there is intermittent narrowing of the bronchi (airways), causing shortness of breath, wheezing, and cough.

The illness often starts in childhood but can develop at any age. At least 1 child in 7 suffers from asthma.

During an asthma attack, the muscle in the walls of the airways contracts, causing narrowing.

The linings of the airways also become swollen and inflamed, producing excess mucus that can block the smaller airways.

allergic Type of asthma tends to occur in childhood and may develop in association with eczema or certain other allergic conditions such as hay fever (see rhinitis, allergic).

Some substances, called allergens, are known to trigger attacks of allergic asthma. Include pollen, house-dust mites, mould, and dander and saliva from furry animals such as cats and dogs.

Rarely, certain foods, such as milk, eggs, nuts, and wheat, provoke an allergic asthmatic reaction

Some people with asthma are sensitive to aspirin, and taking it may trigger an attack.

The 1st attack is sometimes brought on by a respiratory infection.

Factors that can provoke attacks in a person with asthma include cold air, exercise, smoke, and occasionally emotional factors such as stress and anxiety.

Industrial pollution and exhaust emission from motor vehicles do not normally cause asthma, they do appear to worsen symptoms in people who already have the disorder