Allergies

Allergies develop when the immune system identifies a normally harmless substance as a threat and mounts a defensive response. This process is known as sensitisation and typically occurs over repeated exposures.

The underlying causes involve a combination of factors:

• Genetics play a significant role. Allergies tend to run in families. If one or both parents have an allergic condition (such as asthma, eczema or hay fever), their children are more likely to develop allergies
• Environmental exposure to allergens during early life can influence whether the immune system develops tolerance or reactivity. Common allergen categories include pollen, dust mites, animal dander, mould spores, insect venoms and certain foods
• The hygiene hypothesis suggests that reduced exposure to infections and microorganisms in early childhood may contribute to the immune system becoming more prone to allergic responses

Atopy is the genetic tendency to develop allergic conditions. People with atopy are more likely to produce elevated levels of IgE antibodies in response to common environmental allergens. The specific allergens that trigger a response vary from person to person and can be identified through blood testing.