Allergies Health Article

Allergies

A hypersensitive response by the immune system to a foreign substance that is ordinarily harmless.

Allergies account for more office visits to pediatricians than any other ailment, besides the common cold, and are responsible for more missed school days than any other medical problem. It is thought that at least one out of every five children has an allergy of some kind. Allergies are often inherited—a child with one allergic parent has a 25-35% chance of developing allergies, and the likelihood rises to between 50 and 65% if both parents have allergies. The substances that cause allergies—such as dust or pollen—are known as allergens (or antigens). In persons with special sensitivities, they produce elevated levels of immunoglobulin E (IgE) antibodies, which in turn unleash chemicals called histamines that produce allergic reactions. Common allergens include pollen, animal dander, house dust, chemicals, feathers, and a number of different foods.

Allergy symptoms affect a number of different body organs. Skin reactions take a variety of forms—including hives, eczema, and other rashes—but whatever their appearance they are almost always accompanied by acute itching. Respiratory symptoms include a runny, congested, or itchy nose and post-nasal drip, as well as the coughing, wheezing, and shortness of breath that characterize asthma. Eyes may itch, redden, swell, and water. Other allergic symptoms include itching on the roof of the mouth, clogged ears and gastrointestinal problems (nausea, vomiting, diarrhea). Allergies are usually diagnosed either through observation of symptoms, skin tests, or elimination diets, in which different foods are eliminated from the diet in order to discover which ones are causing the problem.

Allergy treatment can be grouped into three broad categories. The simplest is to avoid contact with known allergens. Depending on the type of allergy, this may involve eliminating certain foods from the diet, keeping dust under control by cleaning or by using an air cleaner, making adjustments in pet ownership, or removing trouble-causing items such as feather pillows. The second type of treatment consists of medications, such as antihistamines, that alleviate the symptoms of allergic reactions. A final method is desensitization, more familiarly known as allergy shots, a treatment that exposes an allergic person to gradually increasing amounts of certain allergens over an extended time period in hopes of eliminating or reducing sensitivity to them.

Dealing with allergies at different developmental stages

Childhood allergies pose different challenges to parents depending on the age of the child.

Infancy. Some physicians believe babies are especially vulnerable to allergies because their still-developing digestive systems allow excessive amounts of antibody-producing material into the bloodstream. The first five to six months is the period when an infant is most sensitive to allergens. Nursing is often recommended as a way to reduce the likelihood of allergic reactions, since no infant has ever been found to be allergic to her mother's milk. However, traces of whatever the mother eats are passed on to a baby through nursing, so mothers should be alert to possible connections between allergic symptoms in their babies and foods, medication, or even vitamins they have ingested recently. If a mother becomes convinced that her infant is reacting to a particular substance, she should consider eliminating it from her diet while she is nursing.

When an infant under one year of age develops a rash, the most likely cause is the introduction of an unfamiliar food. Physicians often recommend that solid food be introduced gradually to babies who have a family history of allergies. It is recommended that new foods be introduced one at a time, allowing a 7-10 days after each new food before introducing the next. The later a food item is introduced into the diet, the less likely it is to cause an allergic reaction. In addition, allergic reactions tend to be cumulative: the combination of two or more substances may cause an allergic reaction.

Aside from food, dust, harsh soaps or detergents, ingredients in lotions, and other skin preparations also cause allergic reactions. Parents need to make sure that the items they buy for infant care, such as diapers, lotions, shampoos, and detergent, are free of potential allergens. Many dye- and fragrance-free products are currently available on the market.

Toddlerhood. Toddlers are old enough to become anxious about allergic symptoms, a situation that can trigger further allergic attacks, creating a frustrating cycle. It is important for parents to avoid conveying their own anxiety about allergy symptoms to the child. Toddlers are able to take some responsibility for avoiding foods they are sensitive to, particularly if they can recall being sick after eating certain foods. Parental supervision of toddlers is so extensive that it is relatively easy to control the child's food intake during this stage.

Preschool. At the preschool stage, controlling a child's diet becomes more difficult. By this point, he or she may feel stigmatized or left out when made to eat special foods instead of what all the other children are having. In addition to food, parents should also be mindful of other possible allergens that their child may encounter in preschool, such as playdough or papier-mache made from flour or water, which can pose problems for children allergic to wheat.

School age. Parents of school-age children with allergies should make sure their child's teacher is informed of any important restrictions and emergency procedures. If the child needs to take medication and there is no school nurse, another adult should be designated to administer it.

In the following section, the major types of allergies and allergy symptoms are described.