What causes allergies is not exactly known. Allergies tend to run in families so if either parent has an allergy, the child has a higher chance of getting allergies. However, some children have allergies even if no one in the family does. There is usually a history of contact with an allergen, which is a substance that can be eaten, inhaled, injected or come into contact with the skin. Common allergens include peanuts, pollen, medicines, insect stings and animal dander.

Children have a higher risk of developing allergies than adults, although some children outgrow their allergies as they get older. A family history of allergies and having asthma also increase the child’s risk of allergies.

Allergies are hereditary and passed from parents to children. So a child with at least one parent with allergies is likely to develop allergies. A child with asthma is also more likely to develop other allergies.

Exposure to allergens when the body’s immune system is weak, such as after a viral infection, also seems to increase the risk of allergies.