While asthma genes are inherited in families, the risks of developing the condition are half due to genetic susceptibility and half due to environmental factors.
Yes, a tendency to develop asthma is inherited, but inheritance patterns are still being mapped. The exact causes of asthma are yet unknown, but scientists have developed a range of plausible explanations. The condition runs in families, which means children of asthmatic parents are at an increased risk of developing it. Prevalence rates vary among different ethnicities, suggesting a genetic origin for the onset of the disease.
Though the presence of asthma-related genes suggests a connection, they are not solely responsible for causing the condition. They simply indicate that an individual has a significant risk of developing it, although there is also a chance the person never will. Genes appear to be a more significant factor in childhood cases. However, children who have experienced lung infections in their earlier years are at a greater asthma risk.
It is most accurate to say that the disease arises from a dual gene-environment cause, with gene induced risk factors that include:
- If one of the biological parents has or had asthma, then the chances of a child developing it are greater than those whose parents do not have the condition.
- If both of the parents have asthma, then the child has an even greater risk of developing it than those who have only one parent with the condition.
- If one identical twin has asthma, the other twin (who shares all the same genetic information as their identical twin) is more likely to have the condition. For non-identical twins (who share some but not all their genes in common), both may not develop it.
- The risk of developing asthma is also higher if the child has a first-degree relative with the condition.
Researchers believe that some asthma genes cause the condition no matter what preventative measures are taken or where the person lives. In other cases, asthma genes are inactive and only become active due to some sort of environmental exposure, such as exposure to certain foods, stress, air pollution, tobacco smoke, respiratory infections or allergens. This may explain why some develop asthma in childhood, whereas others develop it later in life.
What are the other causes of asthma?
Apart from inherited genes, several factors can trigger an asthma attack. These factors vary with people and may include:
- Infections: Individuals with a history of repeated viral respiratory infections during childhood are at an increased risk of developing the condition.
- Allergen exposure: Constant exposure to allergens, such as pollen, dust, mites, mold spores, pet dander or cockroach excreta and other irritants, may increase the risk of asthma.
- Other factors:
- Excessive physical activity
- Cold air and changes in temperature and humidity
- Air pollutants, such as smoke and fumes
- Mental stress and strong emotions, such as anxiety, crying or laughter
- Usage of certain medications, such as beta-blockers, aspirin and ibuprofen
- Preservatives added to foods and beverages
- Gastroesophageal reflux disease or GERD can trigger an asthma attack (GERD is a condition where the stomach acids flow back up into the esophagus.)
- Some women say their asthma is easily triggered during their menstrual cycle, but it is still being debated
- Obesity and an unhealthy lifestyle or diet may also cause asthma
What are the common treatment options for asthma?
Long-term control and prevention are key methods to stop asthma attacks before they start. Treatment usually involves recognizing the triggers and avoiding them as much as possible. There is currently no cure for asthma. However, treatment can help control the symptoms so that patients can live a normal, active life.
Inhalers
- This may relieve symptoms when they occur (reliever inhalers) and stop symptoms from developing (preventer inhalers).
- Some people need an inhaler that does both (combination inhalers).
Pills
Patients may also need to take pills if using an inhaler alone is not helping to control symptoms.
- Leukotriene receptor antagonists (LTRAs): LTRAs are the main medicines used for asthma. They come in syrup and powder form.
- Theophylline: Theophylline may also be recommended if other treatments are not helping to control symptoms.
- Steroid pills: Steroid tablets may be recommended if the patient is unable to take any of the above medications to control the symptoms. They may be given as an immediate treatment or as an everyday or long-term treatment to prevent symptoms.
Injections
- For some people with severe asthma, an injection, such as Fasenra (benralizumab), is given every few weeks to control the symptoms.
- These medicines are not suitable for everyone with asthma and can only be prescribed by an asthma specialist.
Surgery
- A procedure called bronchial thermoplasty may be offered as a treatment for severe asthma. It works well, and there are no serious concerns about its safety.
- The procedure involves passing a thin, flexible tube down the esophagus and into the lungs under general anesthesia.
- Heat is then used on the muscles around the airways to help stop them from narrowing and causing asthma symptoms.
- There is evidence that breathing exercises can improve symptoms and reduce the need for reliever medicines in some people, but they should not be used instead of prescribed medicine.
