Blocking Allergy Symptoms: How Pretreatment Works

Tackle allergies before they start, and you could be breathing a lot easier.

Medically Reviewed by Brunilda Nazario, MD on May 20, 2009

For lots of people, allergy treatment is reactive. You get stuffed up, your eyes water, and then you go to the medicine cabinet for relief. But many doctors say that we’ve got it the wrong way around. Instead, we should be taking the medicine before we have symptoms. Call it allergy pretreatment.

“We always tell people to start taking medicine before the allergy season begins,” says Jonathan A. Bernstein MD, an allergist and professor of clinical medicine at the University of Cincinnati. “People often come to me in the middle of the allergy season, and they’re already a mess. Once the symptoms start, they can be like a runaway train.”

By waiting, you could be risking more than mild discomfort. Once allergy symptoms start, you might need more heavy-duty medicine to get them under control. In some people, allergy symptoms quickly turn into allergic sinusitis and more serious problems. That requires even more intensive treatment.

So the key to getting through the allergy season is to have a good defense. By arming yourself with medicine before the trees unleash their pollen -- or before you go visit your sister and their five cats -- you can save yourself a lot of suffering. How does allergy pretreatment work? Here are the answers.

Understanding Allergy Symptoms

Basically, an allergy symptom is the result of your immune system overreacting. It mistakes a harmless substance (like pollen or animal dander) for something more sinister (like a germ or virus) and attacks it. Common allergy symptoms -- like a runny nose -- are collateral damage, side effects of the immune system’s battle with an allergen.

After exposure to an allergen, the immune system releases the chemical histamine into your system. The histamine travels through your blood and latches onto histamine receptors on other cells. Once attached, the histamine causes the cells to swell. This inflammation causes many familiar allergy symptoms. Antihistamine drugs work by blocking the histamine from affecting these cells.

“By taking medicine early, you can prevent the inflammation from starting,” Bernstein tells WebMD. “The drugs block the histamine receptors and the histamine can’t bind with the cells.” Hence, no inflammation and no symptoms -- or at least fewer symptoms.

But if you take the drug after you have allergy symptoms, the histamine has already latched on. It’s already triggered the inflammatory process. Your body has already mobilized for a fight. It can be hard to get it to calm down again. It’s much easier to prevent the reaction than to try to stop it after the fact.

What Is Allergy Pretreatment?

Allergy pretreatment is simple: start taking your medicine a few weeks before the allergy season starts. While they might vary by a week or so from year to year, the pollen seasons are really quite predictable, says Hugh H. Windom, MD, associate clinical professor of immunology at the University of South Florida. So if you know the allergens that trigger your allergies, getting a jump on them should be easy.

“The sooner you get on your medicine, the better,” Windom says. What type of medicine works best for pretreatment of allergies? That depends on your case.

“There’s no ideal drug for preventing allergy symptoms,” Windom says. “Choosing the best drug depends a lot on what worked for you in the past.”

Any allergy medicine can work as pretreatment, more or less. Antihistamines are an excellent choice, experts say. Examples of over-the-counter antihistamines are Benadryl or Claritin. Prescription antihistamines, like the nasal spray Astelin, are another option. Other allergy medicines that work in different ways, such as steroids -- like Flonase, Nasonex, or Veramyst -- can also help.

What if you don’t take the medicine before your symptoms start? Don’t despair. “Being off by a day or two is not a big deal,” Windom tells WebMD. “But don’t wait a whole week, since by then you might already have a cough, and congestion, or worse.”

If you’re pretreating every year, how will you know if you’ve outgrown your allergies?

Don’t worry, says Windom, most adults don’t outgrown chronic allergies. “If you’re in your thirties or forties, and you’ve had an allergy to ragweed pollen for twenty years, it’s not going to be any different next year,” says Windom. Children are an exception, he says, since they can genuinely outgrow allergies.

Obviously, follow your doctor’s directions on how to use your medicine as allergy pretreatment. Typically, you would continue to use it regularly until the season is over.

Preventing Allergy Symptoms: Environmental Control and Allergy Shots

While medicines are important, don’t forget about environmental control. If you can limit your exposure to an allergen, you can prevent or dampen your body’s allergic reaction.

“I think too many allergists don’t bother talking to patients about environmental control,” says Bernstein. “They don’t give their patients enough credit and just prescribe them medicines.” Bernstein says that environmental control should be a crucial part of treatment.

Don’t wait until after allergy symptoms start before making changes to your environment and behavior. As the pollen season approaches, get in the habit of keeping your windows closed. In the spring, install your air conditioners early, since they’re ideal for filtering the outside air that comes into your home.

While most allergy treatments are only temporary fixes, allergy shots -- or immunotherapy -- can offer a more or less permanent solution. By exposing your body to regular, small doses of an allergen -- by injections under the skin -- your immune system can learn to cope without triggering an allergic reaction. Gradually, the doses are increased. Eventually -- and in most cases -- even a large amount of the allergen won’t cause allergy symptoms.

Allergy shots aren’t for everyone. They’re only recommended for people who have allergies more than three months of the year. And they’re not a quick fix, requiring months of injections. But if you’re a good candidate medically and have the willpower, they can be life-changing.

“In correctly chosen patients, the success rate of immunotherapy is over 95%,” says Pramod S. Kelkar, MD, chair of the American Academy of Allergy, Asthma, and Immunology’s Cough Taskforce.

Allergy Pretreatment: The Importance of Control

According to the experts, the secret to living with allergies is being prepared. If you can anticipate when and where you’ll have allergy symptoms, you can often prevent them from developing. This is why allergy pretreatment is so important.

“Controlling allergy symptoms is really important in reducing complications like chronic sinusitis and the progression into asthma,” says Bernstein.

Don’t be passive. Instead, work with your doctor -- or a specialist such as an allergist and immunologist -- and come up with your allergy pretreatment plan.

“Even if you have allergies, you should be able to enjoy the outdoors, your home, your pets, and your job,” says Kelkar. “As long as you take the proper precautions, you should be able to do whatever you want.”

Show Sources


Jonathan A. Bernstein, MD, allergist, Professor of Clinical Medicine, University of Cincinnati, Division of Immunology/Allergy.

Pramod S. Kelkar, MD, FAAAAI, private practice, Maple Grove, MN; Chair of the Cough Task Force of the American Academy of Allergy, Asthma, and Immunology.

Jay M. Portnoy, MD, president of the American College of Allergy, Asthma and Immunology (ACAAI); Chief, Section of Allergy, Asthma and Immunology, Children’s Mercy Hospitals & Clinics in Kansas City, Mo.

Hugh H. Windom, MD, associate clinical professor of immunology, University of South Florida; private practice, Sarasota, Fla.

WebMD Medical Reference: “Allergy Shots.” 

WebMD Medical Reference: “Allergy Medications.”

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