“Many times allergies go undetected,” says Dr. William Neaville, an allergy and immunology specialist on the medical staff at Children’s Medical Center Dallas. Parents mistake the sneezing and watery eyes for the common cold. In allergies, the body’s natural defenses overreact to an otherwise harmless substance, such as pollen. Roughly one person in four has some kind of allergy.

Allergies are seasonal. In the Metroplex, tree pollen causes trouble in the winter and early spring (January to March), grass pollen from early April to mid-June and ragweed from mid-August through late September. The weather can have a big impact.

“Rain will be a real problem for the mold-allergic person,” says Dr. Neaville, “but rain carries away pollen — which hangs in the air when it’s dry.”

Other allergies last year-round, including those triggered by dust and mold. The nose and eyes aren’t allergens’ only targets. The American Academy of Allergy, Asthma and Immunology says doctors diagnose allergic dermatitis (skin rash) in 10 percent children younger than 11, and some 8 percent of kids younger than 6 experience food intolerance.

Some allergies (including those linked to foods or dust mites) can surface before your child’s first birthday, says Dr. Neaville. Others show up later — usually by the early gradeschool years. Allergies also can trigger asthma.

Often, your child’s doctor can help you find out what’s causing the problem by using skin tests. “I think referral to a specialist early on may be very useful to get the child preventive treatment before problems become difficult to control,” adds Dr. Neaville. Once you know the cause, you can modify your home environment to minimize your child’s exposure to triggers like dust mites, mold and pets, which are the cause of most problems in young children. You may also consider medication. The newest generation of antihistamines, for instance, doesn’t cause drowsiness, and some are safe for children as young as 2.