Allergies

What is an allergy?

An allergy is an immune reaction to a substance that is inhaled, injected, ingested or even just touched. The body's immune system responds to an allergen - the substance causing the reaction - by releasing histamines and other chemicals that result in symptoms such as nasal and respiratory congestion, an itchy or runny nose, a sore throat, diarrhoea, itchy, watery eyes, and itchy rashes.

Are allergies hereditary?

The tendency to be allergic is often inherited, although family members may differ widely in the kinds of things they are allergic to. One child may have asthma, while another is prone to diarrhoea. Exclusive breastfeeding for the first six months of your baby's life helps decrease the incidence of allergies in the early years of life.

Are allergies easy to detect?

Not always, and especially not in babies. For instance, many babies develop a wheeze when they get an upper respiratory tract infection. It isn't usually the sign of an allergy, and most babies outgrow the tendency to wheeze when they have a cold as they mature. If the wheeze often occurs in the absence of a cold, and it's still there at age three, your paediatrician may ask you to keep a diary of when your child develops symptoms. Asthma is usually diagnosed through the child's history and response to bronchodilators.

Common allergy-related conditions, such as asthma and eczema can usually be readily diagnosed. However, a person can develop an allergy to almost anything - from cat fur to polyester. Morning congestion which lasts all year long is commonly due to dust-mites or pet allergies. When there are symptoms but no easily discernible cause, you may want to consult your paediatrician.

One way to detect the cause of an allergy is with skin prick tests, especially for allergic contact eczema, but these are unreliable in babies under 18 months old. You may also want to check with your doctor if new symptoms develop or if they persist. If your baby has trouble breathing, pants, appears disoriented, has a rapid pulse or is pale or cold, call your paediatrician immediately.

Will my child have allergies for life?

In some cases, your child will outgrow her allergy. This frequently happens in the case of cow's milk allergy and intolerance. In other cases, the allergy worsens with maturity. Sometimes, a child may develop a new or different allergy later.

How are allergies treated?

While antihistamines and steroids are sometimes used to treat allergies in babies and children, the simplest way to eliminate the problem is to remove the cause. Potential allergens include tobacco smoke, down and feather pillows, perfume, pet hairs, dust mites and (in cooler weather) wool blankets. Your child's stuffed toy collection, which is a real magnet for dust mites, should be washed frequently.

If your child is allergic to airborne allergens, keep him indoors when the haze is especially bad and on windy days, bathe him once or twice a day, and avoid opening the windows on windy days. If eczema is a problem, ask your paediatrician if he would recommend prescribing an appropriate moisturising cream which contains emollients and soap substitutes. Occasionally steroids are used to calm the symptoms.

Pets which cause an allergic reaction should be kept outside, or at least restricted to a certain area of the house. Difficult as it is to contemplate, you may have to consider finding your pet another home.

Keep your baby's room as dust-free as possible. Clean frequently to keep dust to a minimum, though it's not really the dust itself that's the problem but dust mites. Relatives of spiders, dust mites are microscopic organisms that thrive on human skin flakes and produce allergens. While it is impossible to keep all dust at bay, and one effective measure is to open the windows frequently, there are other strategies you may like to try to keep dust mites at bay. These include:

• Don't use carpets or rugs.
• Wash all bedding in hot water.
• Use a damp mop rather than a vacuum cleaner, since many vacuum cleaners kick up the dust.

You can also buy vacuum cleaners with a high efficiency particulate arresting (HEPA) filter to trap dust mites and other allergens.

Food allergies and intolerances

Babies sometimes develop allergies to foods, such as wheat, eggs, milk, soya products, nuts, shellfish, fish and citrus fruit. The symptoms of a true food allergy, such as a rash or wheezing, or swelling of the lips and tongue, generally appear within an hour of eating. If you suspect your baby may be allergic to a certain food, talk to your paediatrician who may refer her for tests.

Babies can also develop intolerances to some foods, which is different to a true allergy. Symptoms of a food intolerance are more likely to affect the digestive system and can include tummy pain, colic, bloating, wind, diarrhoea and sometimes vomiting.

If you suspect your child may have a food intolerance, see your paediatrician, who may refer her to a dietitian. The dietitian may put your child on an exclusion diet, where suspect foods are removed from the diet then slowly reintroduced. This helps to identify which foods are causing the problem.

If your baby is formula fed and is found to have an intolerance or allergy to cow's milk, the dietitian may suggest your baby switches to soya formula or a cow's milk-based formula which has been specially modified for babies with an allergy or intolerance.