Because allergies to pets are common, people long assumed that exposure to pets made allergies more likely. A number of studies have turned this assumption upside down. The August 2003 Pediatrics Synopsis Book summarizes the current understanding.

For a newborn coming into a home, or for a child who has not developed allergies, exposure to a dog or to multiple pets appears to decrease the risk of allergies, eczema, and perhaps (in one study) even asthma. In the studies summarized, as the numbers of cats and dogs went up, hay fever, eczema, and other allergies decreased.

For a child who is already allergic, but not to pets, getting pets does not appear to help or hurt. For a child who is already allergic to pets, there is no allergic benefit to keeping the pets, and exposure will make symptoms worse. If a child has asthma and is pet-allergic, then it may be wise to move the pet from the home.

There has never been a better time to be sure your asthma is under control. With a proper treatment plan, most asthma symptoms can be prevented or minimized. Uncontrolled, the linings of the airways in the lungs can remain inflamed. This is not healthy for the lungs. It can also mimic symptoms of SARS, or make actual SARS worse.

Rebecca Raleigh, an American citizen who was the first suspected SARS patient in India, turned out not to have SARS, but to have a fever from another cause during a flare-up of her asthma. The core symptoms of SARS are fever greater than 100.4 F (38.0 C) and cough (usually a dry cough), difficulty breathing, or other respiratory symptoms. The respiratory symptoms of SARS and asthma can be the same. Toss in a fever, and you either have anxiety – or a real case of SARS.

Keeping asthma inflammation under control can also make it easier for people with asthma to cope with SARS or other lung infections if they are really present.

Asthma is a lung condition where the airways are sometimes tight – a result of airway hyper-responsiveness. Our airways are designed to be responsive to harmful substances in the air. If we walk through clouds of smoke, our airways will shrink, protecting our delicate lung tissues from the noxious ingredients in the smoke. They should return to normal when we begin to breathe fresh air. People with asthma have an exaggerated tightening response.

Different people with asthma respond to different “triggers.” Viral infections are among the most common triggers, especially in young children. Other triggers include smoke, animal dander, pollens, molds, house dust mites, fumes and fragrances, or cold air.

When we exercise, we breathe rapidly and are unable to bring air temperature all the way up to 98.6 degrees — particularly if we breathe through the mouth. Thus, asthmatics who are sensitive to cold air will often wheeze with exercise. (Wheezing, the classic asthma symptom, is the noise made by air moving through these tight airways.) Because asthmatics respond differently to different triggers, their airways are tighter at some times than at others.

Hyper-responsive airways tighten in three ways in response to triggers. First and most immediately, smooth muscle surrounding the airways constricts, narrowing the caliber of the airways. Second, the airways are narrowed by inflammation and swelling of the airway lining. This leads to the third component of airway narrowing, which is the accumulation of mucus and other fluids, which can plug the airways.

The inflammation is the most important part of the disease. It perpetuates the cycle of airway narrowing. It can cause ongoing damage. It also is the slowest to respond to treatment.

Despite clear treatment guidelines, far too many people have uncontrolled asthma. Albuterol is very effective at helping people breath better for the moment, but does nothing to treat the inflammation.

People with asthma who have symptoms more than twice a week, or nighttime wheezing more than twice a month, benefit greatly from using a preventive, anti-inflammatory medicine rather than using albuterol alone.

Certainly, someone who uses albuterol daily should be on a preventive medicine instead or in addition to inhaled albuterol. Preventive and anti-inflammatory medicines are greatly underused for controlling asthma.

If you or your child has asthma, ask that the National Asthma Education and Prevention Program (NAEPP) guidelines be followed. Preventing inflammation prevents damage to the lungs and can greatly improve the long-term outcome.

More infomation on SARS:
SARS – A Worldwide Threat
SARS Update
SARS Hotel
SARS KidsS
top Respiratory Infections
SARS – School’s Out
Preventing SARS
SARS and Allergies
Disease – Severe Acute Respiratory Syndrome (SARS)
SARS Unmasked
Prepare for the Worst; Hope for the Best

Related concepts:

Nasal allergies, Allergic rhinitis, Hay fever, Seasonal allergic rhinitis, Perennial allergic rhinitis, Pollen allergy, House dust allergy, Pet allergies, Mold allergies

Introduction to allergies:

Children with allergies tend to get more ear infections, more colds, and have more sleepless nights than their peers. Far too often, the underlying allergies are missed and children are treated for each symptom as it occurs.

What are allergies?

The lining of our noses contains tiny guardians called mast cells, whose purpose is to protect us from harmful particles in the air we breathe. People with allergies have hypersensitive mast cells that sound the alert in response to relatively harmless particles such as pollen, dust, or pet dander.

When pollen sticks to the membrane of a mast cell of someone with pollen allergies, the cell begins to swell and swell. Finally the mast cell bursts, spilling histamine and many other potent chemicals into the surrounding tissue. These produce the sneezing, swelling, itching, and congestion associated with allergies.

Who gets allergies?

Developing allergies involves a genetic and an environmental component.

Allergies tend to run in families. Asthma, eczema (atopic dermatitis), and allergic rhinitis (hay fever) often occur in the same families. Boys, firstborn children, those with eczema, those with food allergies, and those whose parents have nasal allergies are all more likely to develop nasal allergies. Early wheezing does not appear to increase the chances.

The environment also makes a difference. Allergic rhinitis is an over-exuberant response to substances in the environment. Both too much and too little immune response is unhealthy. Experiences in early childhood can teach the body to set the level of immune protection ‘just right.’

Children who are raised on a farm have a significantly reduced risk of asthma, eczema, and hay fever. Children in day care, those with older siblings, those with pets, and those who get plenty of colds are also less likely to develop nasal allergies.

Recent research has shown a link between fungus exposure and development of allergic rhinitis. Children with family histories of asthma or allergies who were exposed to high levels of fungus, water damage, mold, or mildew were predisposed to develop allergic rhinitis (Environ Health Perspect. 2005 Oct;113(10):1405-9).

Parents are often told that their children are too young to have allergies. While allergies do become more common from ages 2 to 7, they certainly can be present earlier.

What are the symptoms of allergies?

Nasal allergies typically feature a clear nasal discharge with sneezing. There may be itchy, watery eyes and/or a dry cough. Parents often notice a “rabbit nose” — a child crinkling her nose to relieve the itchy sensation inside. The “allergic salute” — rubbing the nose with the hand, sometimes leaving a horizontal crease on the nose — is another common sign. “Allergic shiners” — dark circles under the eyes — have long been associated with allergies, but are less predictive than the other symptoms.

The symptoms tend to be seasonal if exposure to the triggers is seasonal (like pollen), and year-round if the exposure is year round (like pets).

Is allergies contagious?

Probably not. However, we have discovered that some allergic reactions (hives) can be spread by blood transfusion.

How long does allergies last?

While some children outgrow nasal allergies on their own, most will continue to have nasal allergies unless they are treated with immunotherapy.

How is allergies diagnosed?

A careful allergy history and physical exam will usually point to the right diagnosis. Looking at a swab of the nasal secretions under the microscope can confirm the diagnosis.

Common triggers include pollens, molds, house dust mites, and animal dander (their shed skin cells, not their hair or fur!). Identifying your child’s specific triggers can be very important. This can be accomplished with skin testing or with a blood test (RAST). The skin test tends to be very sensitive with immediate results to a broad range of allergens. The results will be affected by allergy medicines the person is taking. The RAST test is less sensitive, more consistent, and offers something of a quantitative analysis of the results.

In infants, a positive result with either test is likely to indicate a real allergy, but a negative test does not give much information. In older children, the opposite tends to be true. A negative test tends to rule out an allergy, while a positive test does not prove one.

Most people think of specific allergies as black and white — something you either have or you don’t. The truth is much more complex. Being allergic to something is a continuum and that continuum changes over time. Most, but not all, food allergies get better over time. Most airborne allergies get more common as children get older. Some allergies peak before puberty and then disappear. Others don’t even begin until puberty is over. Most people who do get tested for allergies have a single round of skin testing. This can provide a valuable snapshot of allergies at a single moment in time, but this just ‘scratches the surface’ of a child’s long-term allergy story.

How is allergies treated?

Treatment revolves around avoiding allergens and irritants, immunotherapy to desensitize people to allergens, and medicines to control symptoms.

If antihistamines are to be used in children, non-sedating antihistamines (such as Claritin, Allegra, or Zyrtec) are usually the best choice in order to minimize the impact on learning. Your pediatrician may recommend nasal sprays and/or eye drops as very effective treatments for decreasing allergy symptoms.

How can allergies be prevented?

Breastfeeding is very effective at decreasing the risk of allergies. Exposure to other children and animals in the first year of life can also lower the risk of allergies.
Once some allergies have developed, avoiding known allergens can calm the immune system and decrease the risk of new allergies.

Related A-to-Z Information:

Adenovirus, Asthma, Common cold, Conjunctivitis (Pink eye), Ear infection, Eczema, Food allergies, Hives, Nosebleeds (Epistaxis), Peanut allergy, Poison ivy/oak/sumac, Sinusitis

Many children are allergic to house dust. But what is it in dust that they are allergic to?

Much of dust is made up of flakes of our old skin. By itself this isn’t a problem, but as we’ve known for a while, many children are allergic to the house dust mite, a tiny creature that lives on the dust.

A significant number of children are actually allergic to mouse, cat, or cockroach allergens found in the dust, according to a  report in the December 2000 issue of the Journal of Allergy and Clinical Immunology.

When trying to get dust allergies under control, removing some of these creatures from the home might make a big difference in helping your children sleep peacefully, all snug in their beds!

At the year 2000 annual meeting of the American College of Asthma, Allergy, and Immunology in Seattle an interesting cat-hair study was presented. People with dark-colored cats were 2 to 4 times more likely to experience moderate or severe allergic symptoms than people with no cats or with light-colored cats.

There was no statistical difference in these symptoms between those with light-hair cats and those with no cats!

I would guess that these results are a reflection of the concentration of cat antigens in the different hair colors: dyeing your cat’s hair won’t help!