Asthma and allergies are common problems in children. One out of 10 children in Hong Kong have asthma, and up to 40% of children have an allergy. The number of children with asthma and allergies has been increasing in the past 10 years. In fact, asthma is one of the main reasons children visit emergency clinic and miss school. These conditions tend to worsen with increased pollution and the emergence of global warming. Your doctor can help you to learn more about asthma and allergies and how to prevent them, provide treatment options and teach you to monitor the severity of reactions

What are asthma and allergies?
Asthma is a chronic disease of the tubes (airways) that carry air to the lungs. These airways become narrow and their linings become swollen, irritated and inflamed. Children with asthma can be sensitive to irritants including viral infection, cigarette smoke, cold air, particles or chemicals in the air and allergens.

An allergy may be a reaction to environmental sources such as house dust, moulds, cockroach, droppings, pollen, grass and animals. Food allergies occur commonly with peanuts, seafood, milk, egg, strawberries and oranges.

Recognizing asthma and allergies:
The symptoms for asthma and allergies may include:
- Nasal congestion
- Coughing at night or early morning
- Fast breathing and/or noisy breathing
- Refusal to participate in physical activities with peers
- Frequent cough and colds which may last for weeks and months
- Recurrent bronchitis and chest infection

For food allergies, common symptoms may include:
- Skin rash
- Swelling of the face and eyes
- Stomach and bowel upset
- Chronic diarrhoea
- Poor growth
- Exercise induced cough

Children with frequent nasal congestion or who have enlarged tonsils or adenoid may develop obstructive sleep apnoea syndrome. Common symptoms of this illness include:
- Loud snoring
- Difficulty breathing during sleep
- Cessation of breathing especially during deep sleep
- Sleep terror, sleep talking, sleep walking may be associated symptoms
- Poor sleep. This may result in poor growth, behavioural and learning problems in school

What are the common tests for asthma and allergies?
Assessments include:
- Peak flow measurement and diary keeping
- Lung function test (for children over 6 years)
- Allergy skin prick test
- Food allergy panel
- Oxygen level assessment
- A sleep study

What medications are used to treat asthma and allergies?
Treatment depends on the nature and severity of the illness.
For allergic rhinitis, antihistamine, steroid nose spray and leukotriene antagonist can be given to reduce nasal congestion. Avoidance of allergens may help to improve symptoms in the long run.

For airway allergies and asthma, long term control or preventive drugs help to reduce airway inflammation. These may include a leukotriene antagonist such as Singulair and inhaled steroid where a long acting bronchodilator may be added to improve control. For quick relief, bronchodilators can be used to relax muscles and open up narrowed airways. These drugs help relieve the feeling of tightness in the chest, wheezing and breathlessness.

For food allergies, treatment is usually with oral antihistamine. As for a life threatening attack, an epipen injection can be used.

How can I tell if my child's asthma and allergy is not being controlled?
The following are signs that current treatment may not be effective:
- Symptoms such as coughing, wheezing, chest tightness and shortness of breath occur more frequently (especially at night and early morning).
- Large changes in peak flow rate measurements (more than 20% change between morning and evening measurements).
- Medications do not seem to relieve your child's cough or breathing problems.
- Your child's asthma attacks last longer and do not easily improve with treatment.
- Your child's asthma attacks quickly become severe.
- You frequently have to take your child to your doctor or the hospital emergency room for treatment of acute asthma.