Taking a Shot at Allergy Relief
by Isadora B. Stehlin
Isn't it a beautiful spring day?
Those words used to drive me insane. Beautiful spring days in Maryland mean warm sunshine and gentle breezes. But drifting in those spring breezes is pollen. So much pollen, mostly from trees, that the air becomes hazy, making life miserable for people with pollen allergies like my son Paul.
Two years ago, sunny spring days didn't mean riding bikes and playing ball for 5-year-old Paul. They meant recess in the school library, a box of tissues at his desk, and eyes nearly swollen shut by the end of the school day. Once home, he took off his pollen-covered clothes, put on clean clothes, and spent his afternoons inside a closed house with air conditioning running even if it was a balmy 70 degrees Fahrenheit (21 degrees Celsius) outside.
Only rainy days were beautiful spring days to Paul.
But last spring wasn't as bad for him, and this spring--after nearly two years of allergy shots--he may finally be able to enjoy sunny spring days outdoors.
One treatment for people with allergies is injections of small amounts of the substances they're allergic to. This is called immunotherapy. Over time as the dose is increased, the patient becomes hyposensitized (less allergic) to the allergens because the body, for reasons not yet fully understood, becomes more tolerant to the offending substances. The symptoms, including sneezing and watery eyes--and the need for medication--are reduced or disappear.
People of any age can develop allergies. Heredity and allergen exposure are important influences in whether allergies develop. Moving from one part of the country to another, especially if the climates, and therefore the native plants, are different, can influence the severity and seasonality of allergic symptoms.
The Food and Drug Administration regulates the biological extracts in allergy shots. The extracts are used both to treat and to test individuals to determine exactly what causes their allergic reactions.
In addition to treating pollen allergy from trees, grasses and weeds, immunotherapy is also used to treat allergies to house dust mites, pets, molds found indoors and outside, and stinging insects such as honey bees, yellow jackets, hornets, and wasps.
Who Should Get Shots?
From the time he was 12 months old, Paul was miserable in the spring and, to a lesser degree in the fall, with a runny nose, watery eyes, and itchy skin. By his third birthday, the pollen allergies also triggered asthma attacks. Prescription medications didn't help much to relieve his symptoms, even with constant use.
All this made Paul a good candidate for injections.
"Shots work extremely well in patients that clearly have allergic symptoms, either allergy in their nose like allergic rhinitis or bronchial asthma, where outdoor allergens like tree, weed and grass pollens seem to be a major cause," says Stanley P. Galant, M.D., an allergist in Orange County, Calif., and a clinical professor and director of pediatric allergy at the University of California, Irvine.
Patients with allergies to molds, house dust mites (microscopic insects that feed on human skin cells found on furniture, bedding and carpets), and animal dander (tiny skin flakes animals continually shed) don't respond quite as well to shots as those allergic to outdoor allergens, he says. But standardization of extracts for cat dander and dust mites and overall better preparations have increased effectiveness even for these patients, he adds.
Immunotherapy doesn't begin until after skin tests or blood tests have determined the exact culprits.
"You have to show that [the patients] have IgE antibodies to the allergens in question," says John Yunginger, M.D., a member of FDA's Allergenic Products Advisory Committee and a pediatric allergist at the Mayo Clinic, Rochester, Minn.
The first time an allergic person is exposed to an allergen, the immune system produces a kind of antibody called immunoglobulin E--IgE for short. (But it is rare for a first exposure to cause allergic symptoms. Only on subsequent exposures do typical allergic symptoms, such as sneezing, coughing and rash, appear.) Overproduction of IgE is characteristic of allergy reactions.
Deciding which allergens to test "depends very much on the patient's history," says Yunginger. "In somebody who has fairly straightforward classical seasonal symptoms they may get as few as 15 or 20 [skin] tests. Someone with more extensive perennial disease may get 75 or 80."
Each individual skin test consists of a small amount of the suspect allergen scratched onto the skin, usually on the back. If a hive with surrounding redness appears within 15 minutes, allergy to the substance is probable. The doctor also takes into account the dose of allergen and the size of the response.
Two controls, standards against which experimental observations may be evaluated, are also used to make sure skin-test reactions are caused by the allergens. One of the controls, which should not cause a reaction (no hive), is simply the diluting solution. The other control contains histamine, a naturally occurring substance that causes a hive in almost everyone.
According to Galant, the patient's history is as significant as the testing. "The history is really what tells me whether to put the patient on shots," he says. "Training as a specialist helps me interpret the data from the history and correlate that with the testing and come up with a solution."
While skin tests give quick results and can be done in the doctor's office, there are some cases where a blood test is preferable, says Marshall Plaut, M.D., chief of the allergic mechanisms section in the National Institute of Allergy and Infectious Diseases, National Institutes of Health. Individuals with skin problems or skin diseases are not good candidates for skin tests, he says.
Once the problem allergens are identified, the allergist prepares a treatment solution containing those allergens to begin the process of desensitization.
"If the patient is very sensitive to a certain allergen, that allergen should be given separately so local and systemic [whole body] responses can be carefully monitored," says Galant. "For example, some people are astronomically allergic to grass pollen." If the grass pollens are in the treatment solution with other allergens, the desensitization to the other allergens might be delayed if reactions to the grass pollens mean maintaining or reducing the solution dose, he explains.
It turned out that Paul was equally and highly sensitive to every tree, weed and grass pollen on the Eastern seaboard as well as dust mites and mold. Only animal dander wasn't a problem. Because he was allergic to so much, he had to get two shots--one containing the pollens, the other with the molds and mites.
The amount of allergen in the first solution the allergist prepares is very dilute. The first shot from that solution is usually 0.05 milliliters, resulting in a minute amount of allergen actually being injected. This cautious approach decreases the chance of adverse reactions.
The shots are given subcutaneously (under the skin) in the back of the upper arm. The regimen usually starts with shots twice a week, gradually increasing the doses as long as no serious reactions occur.
A little bit of redness, itching or swelling (less than 2 centimeters, or the size of a nickel) around the injection site is all right, and the dose may be increased at the next visit. Cold compresses, oral antihistamines, and topical corticosteroids can relieve these minor reactions.
If the site swells more than 2 cm or allergic symptoms develop, the allergist may decide to repeat the same dose at the next visit or even reduce it, depending on the severity of the previous reaction.
The chances of having an adverse reaction to the injection are more common while the doses are being increased than once a maintenance dose is reached, says Yunginger.
Anaphylaxis--a life-threatening reaction that causes blood pressure to plummet, the throat to swell, and airways in the lungs to constrict--is a slight but real risk with allergy shots. A shot of epinephrine--the same drug used to treat severe allergic reactions to bee stings--is used to treat anaphylaxis. Anaphylactic reactions may result in death, although this is rare.
The American Academy of Allergy and Immunology recommends that patients remain in the doctor's office for 20 minutes after receiving the injection, because reactions usually occur within that time. "High-risk patients may have to wait additional time," says Richard Lockey, M.D., director of the division of allergy and immunology at the University of Southern Florida College of Medicine in Tampa.
If no reactions occur, the amount of allergen in each shot is increased until a maintenance dose is reached. For a very sensitive patient, the maximum dose may be the amount the patient can tolerate without a reaction. Others may be able to reach a predetermined amount that researchers have found to be necessary for optimal allergy relief.
Once the maintenance dose has been reached, the intervals between shots can be gradually increased to two, three and even four weeks apart. Reaching the maintenance dose can take anywhere from six months to three years.
The amount of time needed to reach the maintenance dose can be reduced to as little as a few days with "rush" immunotherapy. Patients receive increasing doses of the allergens several times a day for three or four days. This requires close medical observation because the frequent schedule greatly increases the risk of anaphylaxis. That risk, plus the inconvenience of spending several days all at once at the doctor's office or in a clinic, makes rush immunotherapy unpopular with many patients and physicians, says Yunginger.
"If allergy shots are working, the patient normally feels the benefit within a year, sometimes within six months," writes Stuart H. Young, M.D., and colleagues, in the book Allergies (Consumer Reports Books, 1991). "It is usually necessary to continue shots for a couple of years at least, but the idea is to continue only if the treatment is effective, not just in the hope that someday it may help. Fruitless treatment should not drag on for years."
Anywhere from three to five years of treatment is the usual recommendation, says Yunginger.
"The reason for [the three to five years]--and it's not written in concrete--is that the long-term remission of symptoms after the shots stop seems to be better," explains Galant. "If you give a patient shots for a year or two, even if they've had a good year, there's some indication that the relapse rate might be higher."
Galant usually decides to stop shots if the patient has had no symptoms or the degree of symptoms has significantly decreased for about a year. "Generally that's between the second or third year, so when we finish three years, I would seriously consider stopping the shots."
When Yunginger takes his patients off shots, "I have them go through the four seasons to see if the symptoms come back. If the symptoms do come back and can't be completely controlled with medication, then probably the injections should be restarted."
According to Young and colleagues, after stopping shots, one-third of patients will no longer have allergic reactions, one-third will have a partial relapse of symptoms, and one-third will relapse completely.
"Shots are just one part of this therapy," says Galant. "Good avoidance measures are very important."
Usually outdoor allergens can't be completely avoided. Most people can't stay inside all the time, and, in any case, pollen comes inside through open doors and windows and on people's clothes, hair and shoes. Here are some ways to keep pollen out of the house:
Keep all windows closed.
Put a permanent air filter specially designed to keep out pollens and other airborne contaminants in the heating and cooling systems; wash the filter every month.
Change clothes after coming in from outside, and wash the clothes before wearing them again. Keep dirty clothes out of the allergic person's bedroom.
Wash the allergic person's hair every night to avoid transferring pollen from hair to pillow.
Some indoor allergens are also difficult to avoid, but they can be reduced. House dust mites, although they are so tiny you can't see them with the naked eye, can cause big allergic reactions in susceptible people. When it comes to dust mites, "it's hard to get rid of them," says Galant. Mites like to live in box springs, mattresses, pillows, and carpets. To keep the mite population down, the allergic person's mattress, box spring, and pillows should be encased in special covers available from companies that make allergy-proof products. Washable curtains should be the only window coverings. To kill dust mites in bed linens and curtains, wash water must be at least 130 degrees Fahrenheit (54 degrees Celsius). (But during all other times, keep water temperature at 120 F [49 C] to protect children from accidental scalding.) Carpets should be removed or treated with an anti-allergen spray.
For those with allergies to pets, the simple answer, giving up a beloved cat or dog, is often unacceptable. To increase the success of shots, animals should be kept out of the bedroom. Giving pets a weekly bath may help reduce the amount of dander they release into the air.
Whether it means keeping a cat or playing outside in the spring, "my game plan for all patients is to have them live a normal life," says Galant.
That's what I hope will be in store for Paul--time spent outdoors enjoying the sun and spring breezes. For me, it will mean I can finally say, "Yes, it really is a beautiful spring day."
Isadora B. Stehlin is a member of FDA's public affairs staff.