Histamine Hysteria

Allergens can trigger violent reactions during the spring. . . and after

The natural world offers plenty of things for one to be allergic to — especially during springtime — but what all allergies share in common is similar symptoms. In fact, that’s what makes them allergies.

Coming into contact with allergens causes the immune systems of certain people to overreact and produce the familiar effects of runny noses, sneezing, hives and worse. The most common allergies we face are pollens, dust mites, molds, danders and food.

As people head outdoors to get started on spring cleanup and yard work, or head to the baseball diamonds eating roasted peanuts while enjoying America’s pastime, allergy sufferers ought to be on high alert.

University of Mississippi Medical Center experts weigh in on some key allergies and offer helpful facts and tips to reduce their effects.

Fire Ants

One of the best things you can do to avoid a bite from a fire ant is to wear shoes, says Dr. Rick deShazo, chairman of medicine and board-certified in allergy/immunology.

That might sound like obvious advice until you heedlessly trade your sneakers for a pair of flip-flops before washing your car in the front yard.

Now that spring has arrived and with it the renewal of yard work, it’s a good idea to take some precautions against those stinging, lawn-dwelling insects. And if you’re allergic to fire-ant venom, that begins with properly covered feet.

Fifty percent of the population is stung per year in regions where fire ants thrive, deShazo said, so if you live in Mississippi long enough, most likely you will be stung.

Don’t be fooled into thinking it’s enough to stay clear of those ant mounds. Fire ants are scavengers, and a colony’s workers will travel far and wide in search of food. They’re omnivores, meaning they eat anything, and they’re aggressive enough to bite whatever crosses their path, whether it’s another insect, the family pet or your flip-flopped foot.

“Fire ants aren’t native to the United States,” deShazo explained. “They were imported from places like Uruguay and Paraguay, brought into Mobile Bay during the early 1900s.”

And now, they populate the entire southern part of the nation, especially concentrated in the Southeast. That’s because these ants have a very low tolerance for the cold, keeping them from migrating to northern climes.

“They try to,” deShazo said, “but they freeze to death.”

Having an allergy to fire ants, in effect, is the same as having allergies to pollen or peanuts. Part of what defines an allergy is that the symptoms are the same no matter what the cause, says deShazo.

It has to do with a type of antibody the allergen stimulates in the person, called IeG. That antibody, in turn, triggers mast cells to release histamines and other chemicals which produce common allergic symptoms.

Simply put, “certain people who have the propensity to produce IeG are what we call allergic,” said deShazo.

If you are allergic, a fire-ant bite can lead to far worse than itching – it can lead to anaphylactic shock, which can be fatal. 

— M.W.

Kill the Queen

The secret to destroying a mound – or colony – of fire ants is to target the queen. The queen is protected deep below the mound and is fed by her workers.

Some types of ant poisons work too quickly and kill the workers before they can reach the queen. Fire-ant bait with slow-acting poison is the most effective.

deShazo advises against these ineffective methods:

            •  Insecticides,            •  Pouring gasoline on the mound and burning it, or            •  Urinating on the mound.

Stress

A new University of Mississippi Medical Center study plans to test a long-held belief that stress and allergies — particularly asthma — are related.

Dr. Gailen Marshall, professor of medicine and director of the clinical immunology and allergy division, said the question is if stress leads to asthma, a form of allergy manifested in chest congestion.

“We know there’s a high risk of asthma in people who have allergies,” Marshall said. “We know that people under high levels of stress have unbalanced immune systems. And we know stress causes the same immune reactions as do allergies.”

Marshall and other researchers plan to analyze about 150 volunteers, grouping them according to those with asthma, those likely to develop it and those not at risk. If the National Institutes of Health funds the study, Marshall and his colleagues hope to continue tracking the volunteers over 10 years and to include genetic analysis.

Besides comparative data, the long-term study would give researchers a chance to see if stress-management techniques help prevent asthma.

People interested in volunteering in the new study can call (601) 815-5374.

Since stress can tip the balance of immune systems, Marshall said investigators started out to track the immune responses and overall health of 63 survivors of Hurricane Katrina who were enduring persistent, high levels of stress. Unfortunately, federal funding fell through, so researchers have only partial information.

“We have been hearing from doctors on the Gulf Coast, though, that they’re seeing a lot higher incidence of allergy and asthma,” Marshall said. 

— J.M.

Season

It doesn’t take a scientist to determine when the pollen count rises at the Medical Center.

According to the Asthma and Allergy Foundation of America, Jackson was the fifth-most challenging place for spring-allergy sufferers to live in 2008. The Bold New City jumped 25 notches in one year; Jackson ranked No. 30 on the foundation’s list for 2007.

Jackson is located in the “heart” of America’s “Allergy Alley,” according to the AAFA’s list of Spring Allergy Capitals. Foundation members considered pollen scores, medication usage and allergists-per-patient ratios while developing the list.

Nine of the 10 worst places to live with allergies are in the Southeast, a fact that didn’t surprise Dr. Rick deShazo, chairman of medicine, in the least. But deShazo said allergy sufferers may not find much relief during the other seasons, either.

“The temperate climate in the Gulf South distributes the spring and fall pollen seasons seen elsewhere in the U.S. across the year,” deShazo said. “There is some ragweed in the air in the fpring, when it belongs in August and September, and some grass and tree pollen in the fall, when it belongs in the spring.

“In other words, the allergy season lasts all year.” — B.C.

The AAFA’s Top 10 Spring Allergy Capitals in 2008:

1. Lexington, Ky.

2. Greensboro, N.C.

3. Johnson City, Tenn.

4. Augusta, Ga.

5. Jackson. MS

6. Knoxville, Tenn.

7. Birmingham, Ala.

8. New Orleans

9. Little Rock, Ark.

10. San Diego

Peanuts

A study that aims to build children’s tolerance to peanuts received international media attention recently. With an estimated 3 million Americans affected by a potentially fatal allergic reaction to peanuts, there’s no wonder the news generated buzz.

So what are parents to make of this? In a nutshell, a cure for peanut allergy could be on the way.

However, Dr. Anne Yates, professor and chief of the Pediatric Division of Allergy, Asthma and Immunology, said a solution is years away.

Yates, who treats children with food allergies, said the two-year study was conducted under strict protocols, meaning parents shouldn’t try it at home. The findings were released at the American Academy of Allergy, Asthma and Immunology in Washington, D.C.

The study at Duke University, in partnership with the University of Arkansas at Little Rock, found that by feeding them small amounts of peanuts over a gradual period, the children developed a strong tolerance. In the main study, 29 of 33 children reported they can eat peanuts now without developing an allergic reaction. The treatment involved gradually increasing the children’s daily ration to around 15 over the two-year period.

Dr. Stephen Kemp, professor of medicine and associate professor of pediatrics, said the news is encouraging, but more research needs to be done. He said not all peanut-allergic participants in the study saw benefits.

“The amount of peanut tolerance must be kept in perspective,” Kemp said. “Fifteen peanuts, the maximum amount tested and tolerated, is the equivalent of one teaspoon of peanut butter.”

Until a cure is approved for widespread use, Yates still advises parents to avoid giving children peanut products and to keep an epinephrine pen and allergy medication with them at all times in cases of accidental exposure.

— P.S.G.

 

2009-03-31 00:00:00 18881