By Sid Kirchheimer
Reviewed By Michael Smith
When it comes to allergies, the best treatment is obvious to those who administer it -- and largely avoided by those who need it.
An estimated one in three Americans suffers from seasonal or year-round allergies caused by pollen, mold, insects, dust mites, and other common irritants. And allergy shots -- medically known as allergen immunotherapy -- are considered by most experts to be the most effective way to bring long-term relief of allergy symptoms.
With each injection, patients are given increasingly higher doses of the actual allergy trigger until their body becomes resistant to it -- preventing the allergic reaction. By comparison, antihistamines, inhaled steroids, and other allergy medications -- which usually must be taken daily -- treat the resulting symptoms caused by the allergy trigger, but not the allergens themselves.
As Good as or Better Than Drugs
"There have been no good head-to-head study comparisons between immunotherapy and allergy medications," says allergist James Li, MD, of the Mayo Clinic. "Most physicians recognize that antihistamines have significant, but a fairly modest benefit. But the degree of benefit with allergy shots is quite substantial, at least equal to or exceeding many medications."
But despite their effectiveness, allergy shots are largely ignored by most patients, whom either suffer through the allergy season in silence or pop pills to temporarily ease their misery. A survey by the American College of Allergy, Asthma and Immunology (ACAAI) shows that two in three people with allergies would never consider getting allergy shots.
Why People Stay Away
First, there's the allergy testing -- multiple scratches into the skin with different allergy triggers to identify what the person is allergic to. Then there's the time involved -- weekly injections for three to five months to gradually build resistance followed by several years of monthly "maintenance" shots. And there's the pain with each allergy shot.
There's also the time it takes for the allergy shots to show noticeable results; usually, several months after those weekly "building" doses are completed. Relief of symptoms can be seen after a few days of antihistamine pills.
And there's the biggest reason, at least according to most of the allergy sufferers surveyed by the ACAAI three years ago: The cost. Do the math and a doctor's visit -- anywhere from $25 to $100 each, repeated 25 times or so in the first year alone (and then monthly until patients are relatively symptom-free for two years) -- is a lot more expensive than a bottle of over-the-counter Claritin, right? And if insurance doesn't pick up the bill, allergy shots may be all but impossible for some people to afford.
Allergy Shots May Be Cheaper
It's precisely because Claritin has gone over the counter that these days, taking once-a-day medications may be more expensive than allergy shots, say experts.
"Many of the standard medications used for common allergies like hay fever are no longer paid by Medicare, Medicaid, and many private insurance companies," says Myron Zitt, MD, chief of allergy and immunology at the Queens Long Island Medical Group in Babylon, N.Y., and clinical associate professor of medicine at the State University of New York, Stony Brook, School of Medicine.
"The insurance companies say as long as one effective medicine is available over the counter, patients should take it -- and not more expensive prescription drugs," he tells WebMD. "So unlike in years past, they no longer cover those other drugs. The cost has shifted from the insurance companies to the patients."
Meanwhile, allergy shots continue to be covered by insurance companies -- usually in full or with a modest co-pay. But even before Claritin went over the counter and changed the insurers' rules, allergy shots still seemed to make good economic sense, at least in the medical community.
In April 2000, Respiratory Reviews published a study indicating that a patient's out-of-pocket drug costs for treating year-round allergic rhinitis was $1,200. But researcher Timothy J. Sullivan III, MD, of Emory University, calculated that the same patient would pay only $800 for the first year of allergy shots -- the most expensive year. In following years, when allergy shots are done monthly or even less frequently, those costs drop to between $290 and $170. Over six years, that amounts to a $1,300 to $2,900 savings with allergy shots, that study shows.
And there's the August 1999 study in The New England Journal of Medicine that shows allergy shots to treat grass pollens can provide up to three years of additional relief after treatment has ended. "Once you stop antihistamines and other drugs, you're right back where you started," says Zitt. Even a couple of missed doses can do that.
Allergy Shots and the Triggers They Fight
Allergy shots are effective against all sorts of allergy triggers that float in the air, including:
- Tree pollens
- Grass pollens
- Weed pollens
- Mold spores
- Dust mites
- Cat dander
- Insect stings
But when it comes to other types of allergy triggers -- such as food allergies and skin reactions -- there is not enough research to support allergy shots, according to the American College of Allergy, Asthma and Immunology.
Before allergy shots begin, allergists identify the specific allergen(s) with the skin scratch test, avoiding a common problem; patients who "self-diagnose" themselves, and may reach for antihistamines under the assumption they have seasonal hay fever when they could also be allergic to year-round dust mites, mold, or cat dander.
Allergy shots benefit some patients more than others. Those with hay fever tend to fare best, with more than 90% getting "significant" relief, says Li. Allergy shots are also extremely effective for mild-to-moderate asthma, specifically when attacks are caused by allergies, or bee sting and other insect sensitivity.
"Allergy shots are also effective for those with cat and dust mite allergy, but the challenge there is that there continues to be significant continued exposure -- and avoidance of the allergen is the most important factor in preventing symptoms," Li tells WebMD. "That's what makes mold allergies especially difficult. You really need to stop leaky pipes and other sources causing mold. That's why I personally have less confidence in mold allergy shots compared to the excellent results seen for pollen, cat, and dust mites."
Although there is a minimal risk of severe allergic reaction from allergy shots, the injections pose little risk as long as they are administered with slowly increasing doses. The reason why allergy shots typically take three to five years is because giving more "hefty" doses in a shorter time frame could trigger potentially life-threatening anaphylactic shock -- an intense reaction to an allergy trigger in which the airway can close.
Who Should Avoid Allergy Shots
Allergy shots are not recommended for those with heart disease or severe asthma. In addition, allergy shots should not be started during pregnancy but can be continued during pregnancy if they started before conception.
"If there's an adverse reaction during immunotherapy, you have to give adrenaline," says Zitt. "And you don't want to do that during pregnancy, to heart patients, or those with severe asthma. But if you're not building up resistance, there's not that concern and allergy shots are extremely safe, well-tolerated, and highly effective for most people with allergies."
Originally published Aug. 22, 2003.
Medically updated Feb. 22, 2005.
SOURCES: Myron Zitt, MD, chief of allergy and immunology, Queens Long Island Medical Group, Babylon, N.Y.; clinical associate professor of medicine at the State University of New York, Stony Brook, School of Medicine; vice president, American College of Allergy, Asthma and Immunology, Chicago. James Li, MD, professor of medicine and consulting physician, division of allergic diseases and internal medicine, The Mayo Clinic, Rochester, Minn. American College of Allergy, Asthma and Immunology patient survey, November 2000. Respiratory Reviews, April 2000. The New England Journal of Medicine, Aug. 12, 1999.