Fortunately, severe or life-threatening allergies occur only in a small group of children. It typically develops by age ten and reaches its peak in the early 20s, with symptoms dissipating by the 40s to 60s. Dust mites are one of the most common causes of allergies and are present year-round. Dust comprises many particles and can contain things such as fabric fibers and bacteria, as well as microscopic dust mites. The dust mite is the main allergic component of house dust.
Dust mites live in bedding, upholstery, and carpets.
Cockroach body parts and waste products are also a major household allergen, especially in inner cities. Asthma rates of inner city children are high due to air pollution and also cockroach exposure in overcrowded buildings. Pollen is another important cause of allergies. Trees, weeds, and grasses release these tiny particles into the air to fertilize other plants. Most people know pollen allergy as hay fever or rose fever.