How Allergies Work
By the time children are 3 years old, 20 percent of them have symptoms of upper respiratory allergies, and that number goes up to 42 percent by age 6. However, even children who are 2 and younger can develop allergic symptoms such as a rash or coughing and wheezing, in reaction to something they've been exposed to (at this age, most likely a food). But the good news is there's a lot you can do to get allergies under control -- and even prevent them in the first place.
The first step is knowing how allergies work. The body's immune system is programmed to produce antibodies to fight viruses, bacteria, and toxins. The swelling and itching you feel at a wound site is the body sending chemicals there so the injury can heal. But sometimes the body reacts to a harmless everyday substance, like a bite of egg or dust particles in the air, as if it were a dangerous invader. It sends chemicals to swell the lining of your nose, for example, if it's something you've inhaled, causing you to sneeze. Or if it's something you've eaten, your gastrointestinal lining gets inflamed, possibly leading to diarrhea.
Babies can't let you know what's bothering them or how they're feeling, so detecting an allergy is often difficult. Here are some common questions I get from parents in my practice.
How do I know if my child is allergic to his formula?
Allergy symptoms can appear from the first few weeks to the first two months, depending on how sensitive your child is to the milk protein casein -- usually the cause of an allergy to cow's-milk formula. Typically children will suffer from stomach cramps that make them cry, get cranky, and spit up after feedings. Loose stools and diarrhea, as well as blood in the stool, are also common symptoms. Some children may also break out in a rash, hives, vomit, eczema (dry, flaky patches of skin especially around the forehead) or even have difficulty breathing in severe cases, called anaphylaxis. In other instances the only sign of a cow's-milk formula allergy is that your child becomes continuously irritable or cries after eating -- and when you offer another bottle to soothe him, that only makes things worse. If your doctor suspects a milk allergy, he will probably suggest you switch to a soy protein-based formula or a hydrolyzed cow's-milk formula, in which the milk proteins are broken down enough so that your baby can tolerate them.
I'm pregnant, and I've always been allergic to peanut butter and seafood. Does that mean my baby will be allergic to those foods, too?
Since allergies are often inherited, it is a good idea to learn more about how common they are in your family, as well as in the family of your child's father. If there is a history of food allergies, the chances are greater that your baby will develop them, too. In fact, if both the father and mother have allergies, there's about a 60 percent chance that their baby will have allergies. If only one parent has them, the odds are 30 percent. It is also more likely that your child will develop allergies to peanut butter and seafood if you have them, but that's not absolute.
My 1-year-old is allergic to milk. Can I give him foods that contain milk, such as pancakes or biscuits?
It depends how severe your child's milk allergy is. As mentioned before, a child who is allergic to milk is usually allergic to the milk protein casein. Since the heat from cooking may alter or destroy the milk proteins, your child may be able to tolerate the milk in pancakes or biscuits. However, if he has severe allergies, cooking the milk may not be enough. The Food Allergy and Anaphylaxis Network (foodallergy.org) provides more information on what's safe for allergic kids to eat.
I have food allergies. While I'm expecting is there anything I can do to prevent my baby from getting them?
Generally, if you're concerned about your baby's developing food allergies because there is a family history of them, you should be careful about what you eat during the third trimester. Although it may be difficult, it's wise to cut down on the amount of potential allergens you eat, including milk, eggs, wheat, soy, tree nuts (walnuts, cashews, etc.), peanuts, fish, and shellfish. These foods account for up to 90 percent of all allergies in children younger than 2. Breastfeeding for the first year is also a good idea. It's been shown to reduce the incidence of allergies in babies. Despite any concerns about your diet influencing a future food allergy for Baby, it's unnecessary to eliminate allergenic foods from your diet unless determined necessary by your doctor. Also, children who are at high risk of developing allergies, specifically those whose parents or siblings have allergic diseases, might benefit from being introduced to solids, especially allergenic foods, later. (For example, although egg yolks are OK to try, egg whites should be reserved for when your baby is a little bit older and exposed to more solids.)
Do I have to worry about my child's food allergies? Won't she outgrow them?
In most instances food allergies do disappear as a child gets older, often by age 5 according to the AAP.
Nasal Stuffiness & Rashes
My 18-month-old daughter has a stuffy nose that just won't go away, and she sometimes vomits first thing in the morning. I thought it was a virus, but could it be allergies?
While a cold may be causing your daughter's stuffy nose, typically if symptoms go on for more than five to seven days, allergies often are the culprit. When an allergy causes congestion and a runny nose, some of the mucus drips to the back of the throat. This is called postnasal drip. Young children who can't spit up the mucus may swallow it and end up vomiting up the mucus, since it's irritating to the stomach. That sounds like what might be happening to your daughter. Talk to your pediatrician or a pediatric allergist, who will take a case history of her symptoms to look for the cause of the allergy. It may be something in her environment, such as dust mites, or animal dander.
You can cleanse her nose by moistening her nasal passage with saline drops. Then suction out the mucus using a nasal aspirator. Keeping a vaporizer or humidifier in her bedroom will also help to keep her nose moist and will make the mucus easier to dislodge. Your doctor may also suggest an antihistamine such as Claritin or Zyrtec liquid, medications which help cut down on the allergic symptoms.
My 7-month-old had a cold and was wheezing overnight. We took him to the emergency room and he was given albuterol, an asthma medication. Does this mean he has asthma?
Not necessarily. Wheezing is a high-pitched sound that occurs when the millions of tiny airways in the lungs narrow, sort of like what happens when you blow into a narrow instrument like a flute. Babies already have tiny airways that narrow even further when they swell up due to a cold or other infection, making children wheeze as they breathe with difficulty. So wheezing is common in babies and may not be a sign of asthma. (The medicine albuterol is a bronchodilator that relaxes the muscles of the airways and increases air flow to the lungs so your child can breathe.)
However, children who frequently wheeze when they get a cold may have asthma or develop asthma. (If you're concerned at all about your child, you should be sure to speak with your pediatrician for more information.) Asthma is more likely if there is a family history of allergies or asthma, or if your child has already shown signs of a food or other allergy, such as eczema or hives. Although some episodes of wheezing occur once and never again, if the problem recurs, it's more likely that your child does have asthma. Asthma is a chronic respiratory disease in which a person's airways become inflamed, the muscles around them tighten and this causes the airways to narrow and cut down on the air flow to the lungs. The swelling also can worsen, making the airways even narrower. Cells in the airways may make more mucus than normal. Mucus is a sticky, thick liquid that can further narrow your airways. Asthma attacks also referred to as flareups or exacerbations can occur when exposed to common triggers such as dust, mold, and animal dander, as well as cold viruses. As the inflamed airways spasm, Baby coughs and/or wheezes as he struggles to breathe. To be safe, have your child evaluated by a pediatric allergist or pulmonologist.
Also, asthma is more likely if there is a family history of allergies or asthma, or if your child has already shown signs of a food or other allergy, such as eczema or hives. Some episodes of wheezing occur once and never again; if the problem recurs, it's more likely that your child does have asthma.
Asthma is a chronic respiratory disease in which a person's airways become inflamed, the muscles around them tighten and this causes the airways to narrow and cut down on the air flow to the lungs. The swelling also can worsen, making the airways even narrower. Cells in the airways may make more mucus than normal. Mucus is a sticky, thick liquid that can further narrow your airways. Asthma attacks also referred to as flareups or exacerbations can occur when exposed to common triggers such as dust, mold, and animal dander, as well as cold viruses. As the inflamed airways spasm, Baby coughs and/or wheezes as he struggles to breathe. To be safe, have your child evaluated by a pediatric allergist or pulmonologist.
My pediatrician says my 5-month-old baby has eczema on her cheeks, but we can't figure out what's causing it. What should we do?
Eczema, which usually appears in baby's first year, is a red, rough, itchy patch of rashes usually found on an infant's cheeks, scalp, and forehead. It may spread to other parts of the body, such as behind the knees, chest, and in the bend of the arm. It is often caused by allergies to foods, but you're right that the culprit is often not apparent. The rash can also be aggravated by heat, irritants that come in contact with your baby's skin such as wool or the chemicals in some soaps, lotions, and detergents, changes in temperature, and dry skin. Think about whether your baby ate any new food recently or, if you're breastfeeding, whether you ate anything new. In the meantime, to treat the skin, keep it moist with a cream such as Eucerin. If the inflammation is severe, your doctor can prescribe a non-steroidal cream for short or intermittent-term treatment, which is preferable to the older, steroid-based creams used to treat eczema -- they can cause discoloration and thickening of the skin if used for too long.
Does having a pet make allergies worse or better?
Having a pet in the home, particularly a cat or a dog, may contribute to problems with allergies and asthma if there is a family history of allergies. Cats are very allergenic animals, as they leave their fur (containing the offending dander) everywhere. If a parent has an allergy to animals, the child is more likely to develop one.
You're probably confused because some recent studies have suggested that having a cat or dog in the house at an early age may be beneficial to your child, not only allowing him to tolerate the animal, but also offering protection against his developing allergies. However, these studies need to be repeated to confirm the findings. As of right now we recommend not having pets in the home if there's a family history of allergies.
Can babies and toddlers have seasonal allergies to grass and pollens?
The general rule is that it takes at least one season for the immune system to "learn" to be allergic. So subsequent seasons may be a problem. For example, a June baby may not react to ragweed at 3 months of age when he's exposed to it for the first time, usually in late summer and early fall, but the next time -- when he's around 15 months old -- he may develop allergic symptoms. Exposure to other allergens such as cat dander or mold may be constant, so in those cases, a child is likely to develop allergies to them at any time.
Prevention & Treatment
What kinds of allergy medications can young children take? What are other ways to control their allergies?
Not all adult allergy medicines are appropriate for children. Claritin, which is now available over the counter, is a very good antihistamine that may be used for children over 2. (For children under two consult your pediatrician.) Zyrtec is a prescription antihistamine that may be used from the age of 2. Benadryl also works to stop allergy symptoms but can make children sleepy or wired (before administering to your child, be sure to contact your doctor for safety and dosage information).
Other medications approved for children 2 and up include Nasonex, a nasal corticosteroid that is sprayed into the nose. This medicine relieves the inflammation in the nasal passages that causes congestion and a runny nose. Pulmicort Respules, an inhaled corticosteroid, is approved for bronchial asthma. This medicine relieves the swelling in baby's airways so he can breathe more easily.
Obviously, the best way to beat allergies is to avoid whatever is causing the reaction. But this can be tricky. A few years ago, I had a patient in pre-K who was worse on the weekdays while he was in school and better on the weekends. He was found to be very allergic to cats and dust mites, and we discovered that of the other 11 kids in his class, 7 had cats at home. In class, he napped on a rug on the floor where children with cat dander on their clothes also napped. The secondhand animal exposure and the dust mites in the rug were a disaster for him. The only solution was to switch schools.
Using a HEPA filter in your home, which filters the air of the tiny particles that cause allergies, can help. (Skip the cheap air purifiers found in department stores -- they don't work well.) Try using dust-mite covers on the bed and pillows if your child is sensitive to dust. Also store dust-collecting stuffed animals in a closet, rather than out on shelves, and use area rugs instead of wall-to-wall carpeting. In addition, it's important not to smoke at home, because cigarette smoke can aggravate allergies.
My pediatrician wants to refer my 2-year-old to an allergist for skin testing but I'm afraid of his skin being scratched. My doctor says he can also perform a blood test that detects allergies in his office. Is that just as good?
If your pediatrician feels that your child should be tested for allergies, either a blood test or skin testing is fine. The blood test involves taking blood from a vein, usually in the arm. It's a little stick and lasts a few moments.
Skin tests are slightly painful but are soon forgotten by the child -- and the parent. You will learn the results in about 20 minutes, but may have to wait a few days for the results of a blood test.
Skin Prick Test: The doctor places a drop of a solution that has the allergen on the skin, and a series of scratches or needle pricks allows the solution to enter the skin; if a wheal pops up then this is considered positive reaction.
Intradermal Test: A small amount of the allergen solution is injected into the skin. An intradermal allergy test may be done when a substance does not cause a reaction in the skin prick test but may still suspected as an allergen.
Skin Patch Test: The allergen solution is placed on a pad that is taped to the skin for 24 to 72 hours. This test is used to detect a skin allergy contact dermatitis.
Whichever you choose, it's best to go to an allergist for either test, because just as important as the test is the interpretation of the results. These tests are a backup to the complete medical history and physical exam taken by an allergist. Your allergist will ask questions about when, where, and how often the reaction occurred. He can often determine the likely cause of an allergy from these answers and from examining your child -- the test simply confirms what he may already know.
It seems that more and more kids have allergies these days. Why is that?
Part of the answer is that we are much more aware of what allergies are than in the past, so more people seek treatment for allergies and doctors are better at diagnosing them. We are also exposed to a greater variety of allergic substances -- for example, we eat many more foods today than in the past. A hundred years ago or so, for instance, you wouldn't have been able to get lobster if you grew up in the Midwest, so you would never have become sensitized to seafood. In addition, today we tend to seal ourselves into our homes for insulation from heat and cold, which means we get less fresh air flowing in and are exposed to greater concentrations of allergy-causing substances (called allergens), such as dust and animal dander.
Paul Ehrlich, MD, is a pediatric allergist in New York City, and coauthor of What Your Doctor May Not Tell You About Children's Allergies and Asthma (Warner).
All content here, including advice from doctors and other health professionals, should be considered as opinion only. Always seek the direct advice of your own doctor in connection with any questions or issues you may have regarding your own health or the health of others.
Originally published in American Baby magazine, April 2004. Updated February 2010