Allergies

What are allergies?

The immune system protects us from harmful substances such as viruses and bacteria. An allergy is a type of strong immune response to a substance that is not harmful to most people. This substance is known as an allergen.

For children with an allergy, the body’s immune system overreacts and treats the allergen as an invader. This results in symptoms from mild discomfort to severe distress.

Allergic disorders, including food allergies, are common in childhood. Far more people have a food intolerance. A food intolerance is an unpleasant symptom triggered by food. It does not involve the immune system. Many children with allergies also have asthma.

For more information, please read Asthma.

Types of allergens

Common airborne allergens

Dust mites are common airborne allergens. These tiny bugs live in warm, damp, dusty places in your home. They eat dead skin cells. Their waste is a major cause of allergies and asthma.  Other common airborne allergens include:

• pollen from flowers and other plants
• mould
• pet dander (dead skin cells from pets)
• cockroaches

Common food allergens

The most common food allergens include:

• peanuts
• tree nuts such as hazelnuts, walnuts, almonds, and cashews
• eggs
• cow's milk 

Fish, crustaceans, and mollusks are also common allergens.

Even small amounts of these foods can trigger anaphylaxis in some allergic children. Anaphylaxis (say: anna-fil-AX-iss) is the most severe type of allergic reaction (see below). Allergens can also be hidden in common party dishes like cookies, cakes, candies, or other foods. Always ask the cook or the host if dishes contain foods your child is allergic to.

Other common allergens

• insect stings
• medicines
• chemicals

Signs and symptoms of allergies

Allergic reactions will vary in severity from allergy to allergy and child to child. Where you live can also affect the type and severity of the allergy.

Allergy symptoms vary, but may include:

• breathing problems
• burning, tearing, or itchy eyes
• conjunctivitis (red, swollen eyes)
• coughing
• hives (raised, red, itchy bumps)
• itching of the nose, mouth, throat, skin, or any other area
• runny nose
• skin rashes
• wheezing
• swelling around the face or throat
• shock

Airborne allergens

Airborne allergens usually cause sneezing, itchy nose or throat, nasal congestion, red and itchy eyes, and coughing. Some children also have wheezing and shortness of breath.

Food allergens and insect bites

Your child’s response to a food allergy or insect bite will depend on the degree of sensitivity to that food or bug. Symptoms can include:

• itchy mouth and throat when food is swallowed
• hives
• a rash that looks like eczema
• runny, itchy nose
• difficulty breathing
• swelling around the face or throat
• going into shock

Causes

Allergens may come in contact with the skin or be breathed in, eaten, or injected.

When the body detects an allergen, it signals the immune system to produce antibodies called immunoglobulin E (IgE). Those antibodies cause certain cells in the body to release chemicals called histamines. Histamines swim through the bloodstream to defend against the invading substance or allergen.

Your child’s allergic reaction depends on which part of the body was exposed to the allergen. Most commonly, allergic reactions affect a child’s eyes, nose, throat, lungs or skin.

Anaphylaxis

Some allergies, in particular food allergies, can be severe and life-threatening. If the sensitivity to an allergen is extreme, your child may experience anaphylaxis within seconds of being exposed to the allergen.

Anaphylaxis is the body’s quick and strong defense in response to the allergen. This response can be so strong it can be dangerous. The antibodies released during anaphylaxis may cause difficulty breathing, swelling, or a drop in blood pressure (shock).

Fast treatment with a medicine called epinephrine (pronounced: epp-in-EFF-rin) can stop this process and save your child’s life. This medicine is commonly known as the Epi-pen. Anaphylaxis is an emergency. Your child needs to go to a hospital right away.

What your child’s doctor can do for allergies

In order to determine your child's allergy, your child’s doctor will usually do a physical exam of your child. The health provider will then ask for your child’s allergy history, and ask for a description of the allergic symptoms. Your child might then be tested. The tests may include skin tests, blood tests, chest X-ray, lung function test, or exercise tolerance test. The doctor will make a diagnosis based on the test findings. Then the doctor will meet with you and your child at a later date to discuss the findings.

Preparing for your appointment

Your child may need to stop using medication for a certain amount of time before the allergy test. These medications may include antihistamines and other pills for motion sickness. Ask your doctor if your child should stop taking medications before the visit.

Taking care of your child with allergies at home

Treat your child’s allergy with the medicine advised by your child’s doctor. If your child has a rash, calamine lotion or cold compresses may relieve the pain and irritation. Antihistamines (such as Benadryl or Chlor-tripolon) can also relieve the pain or itching. These medicines may cause your child to become sleepy.

If your child has a severe allergy, your doctor might give you a prescription for an epinephrine self-injection pen (Epi-pen). Your doctor can show you how and when to use the pen. You or your child may need to carry one at all times.

As much as possible, reduce your child’s contact to allergens. The steps you take depend on what your child is allergic to. Discuss this with your child’s doctor.

Airborne allergens

Some options for reducing your child’s contact with airborne allergens include:

• Have a pet-free home. Or if you have a pet, keep it out of the child’s room and bathe it regularly.
• Remove carpets and rugs from the home, especially from your child’s bedroom. Hard floor surfaces do not collect dust as much as carpets do.
• Reduce the relative humidity in the home.
• Wash bedding in hot water. This will help reduce dust mites.
• Control contact with outdoor pollen by closing windows in peak seasons. Use an air conditioning system with a small-particle filter.
• Get rid of items in the home that collect dust. These include  heavy drapes or old, unclean furniture.
• Clean your home often.
• Seal pillows and mattresses if your child is allergic to dust mites.
• Keep bathrooms and other mould-prone areas clean and dry.

Food allergies

If your child has a food allergy, teach your child to be aware of the foods to avoid. You and your child should learn to read labels and ask questions about served food. It is also important to inform all caregivers of your child’s allergy and any restrictions on your child’s diet.

Prevention

Your child must avoid all foods they are allergic to. Some children may outgrow their allergies. Others may have to avoid the antigen for life. Avoiding of a food antigen can be difficult. Many children unintentionally eat food they are allergic to. It is important for your child and those around him to be aware of the allergy. They need to be alert to food that may cause a reaction.

When they are old enough to read, children should read labels on food packaging. They should be taught to understand the importance of looking for the food antigen in the product ingredients.

A word about infants

If there is a family history of eczema and allergies in a parent or sibling, discuss infant feeding with your child's doctor.

When to seek medical assistance

Take your child to the nearest Emergency Department if your child has any of the following:

• trouble breathing
• swelling, particularly of the face, throat, lips, and tongue
• rapid drop in blood pressure
• dizziness
• loss of consciousness
• hives
• tightness of the throat
• hoarse voice
• lightheadedness
• received epinephrine, since the symptoms can start again hours after the epinephrine is given

Key points

• Your child will undergo tests to determine whether he has a severe allergy.
• To reduce your child’s exposure to allergens, have a pet-free home and remove carpeting.
• If your child has a severe allergy, make sure to allert teachers and other caregivers.
• Always have the Epi-pen on or near your child in case of an emergency.
• For less severe allergy symptoms, over the counter medicines can provide relief but may make your child sleepy.