Allergies Allergies come in many forms. A child with allergies may snore, wake with a sore throat, breathe through the mouth, and frequently rub his or her nose. Allergy symptoms are often like cold symptoms, but usually last longer. The most common cause of allergies are particles in the air, such as pollen, house dust mites, mold or mildew, and animal dander.
Allergies seem to run in families.
Hay fever is the most common allergy. Parents with hay fever often have children with allergies. Hay fever usually develops in childhood, but can occur at any age. You can often discover the cause of an allergy by noting when symptoms occur. Allergies that persist all year long may be due to dust mites in household dust, mold spores, or animal dander.