Allergy

General Information

The most common environmental agents causing problems with allergies include: Dust, dust mites (microscopic bugs that exist in dust), mold, animals, pollen and cockroach.

Foods are occasionally a problem, but treatment of food allergies remains controversial. Food allergies tend to occur more commonly in childhood, and tend to lessen as kids get older. They can cause a variety of problems from eczema to asthma; whether they cause problems with hyperactivity is a subject of great debate. There is a group of physicians called clinical ecologists who believe that food and chemicals cause a wide variety of symptoms, from hypersensitivity to depression, whereas most traditional allergists do not believe they cause that many problems. This forum is not one to address the issues other than to say that disagreement occurs.

Occasionally other medical diseases (e.g. pregnancy or thyroid problems) will cause allergy-like symptoms, so its often important for an allergist to be aware of other medical problems which you may have.

When patients have allergies which may be due to environmental agents, foods, or several other agents, allergy skin tests can be very helpful in pinpointing the exact cause. Some allergists use blood (RAST) tests instead of skin tests. We won't go into all the reasons but most allergists like me think they are less reliable under most circumstances. There are a few exceptions: in patients with severe allergies, bad skin problems, the very young or old and those who can't stop antihistamines and some other medications, the blood tests may be helpful. (Antihistamines interfere with interpretation of the skin tests.) Blood tests are, however, much more expensive.

Typically patients have skin tests done with a variety of different agents which commonly cause allergies. These may include dust, dust mites, molds, trees, grasses, weeds, animal dander, cockroaches, foods, and the clinical ecologists may test with chemicals (which is controversial). If you have skin tests done, you may need to stop antihistamines and some other medications before your testing is done, because the antihistamines can make you less reactive to allergens.

Skin tests are usually performed by either pricking or scratching the skin with a needle after a small amount of a liquid extract of the agent to be tested has been placed on the skin (these liquid extracts are made by various allergy supply companies). After waiting a short period of time, the allergic reaction can be detected based on the size of the welt and the size of the redness at the site of the prick. This correlates well with respiratory allergies. In addition, intradermal tests may be done in which a small amount of the extract is injected just underneath the skin to form a small welt. The size of the reaction can then be used to determine whether an allergy exists.

Allergy testing for foods is similar to environmental agents, but most allergists do not give allergy shots for foods except on an investigational basis. Clinical ecologists do give food and chemical shots but it raises the hair of traditional allergists - As I discussed above - we'll avoid dealing with it. For the most part, avoidance of foods is suggested by traditional allergists, although some medications can be helpful.

Allergy shots are extremely helpful for reducing symptoms in patients who have continuing symptoms despite medication, fatigue due to allergies, who don't respond to medications or have complications like sinusitis. Allergy shots also are commonly preferred by patients who would rather not use drugs, as the shots are made of an extract of the very things that people are allergic to, e.g. dust mites, pollens, molds, etc. In addition, allergy shots have also been shown to be effective for people with cat allergies, but avoidance is still the best treatment for cat allergies. In addition, allergy shots do not replace the environmental controls discussed above.

If it is decided that allergy shots make sense, patients are given injections of the allergens which cause problems. The shots are less painful than a mosquito bite, and now we have creams that can numb the skin before getting the shot. Most patients can also use ice to numb the skin, if necessary. Believe me, you barely know you've gotten an injection. In general, shots are initially given once or twice a week. Each time the amount injected will be increased slightly until a maximum or maintenance dose is reached. Shots are generally continued with this frequency for anywhere from 3-12 months and then less frequently. Eventually, most patients take their shots only every 3-4 weeks.

In general, allergy shots may take months to a year or two to start working and patients should continue shots for at least 5 years. Because many patients will have a return of symptoms if they stop the shots, some patients will choose to continue them indefinitely. Allergy shots take a long time to work, so if you start on them, BE PATIENT. Most allergists (including me) don't like patients to self administer shots, as serious reactions can occur, so they should be given by a doctor. If you get shots, make sure that you tell the nurse or doctor about any reactions to the shots, any current illnesses and any medications that you're taking. And be sure to wait for 15 - 30 minutes in the office after the shots. Your doctor may also give you adrenalin to self inject in case you have a problem after you leave the office.

Stinging Insects

Patients who have serious reactions to stinging insects should have allergy tests done to determine if they are allergic to stinging insects. A small reaction at the site of a sting is not considered a significant reaction, but symptoms such as asthma, difficulty breathing, shortness of breath, or a drop in the blood pressure indicate an increased likelihood of having life threatening reactions with future stings. Hives in adults have also been shown to be a significant potential problem, but not in children.

One important thing to remember when removing a stinger from a bee sting ( honeybees leave their stinger in) is to remove it as soon as possible, as the longer the stinger is left in place, the more venom is injected by the stinger.

Patients who have these kinds of reactions are typically skin tested with stinging insects (which may take several hours). Skin testing is similar to the testing done for environmental agents. If skin testing shows that someone is allergic, they may be started on a series of shots to desensitize them to the various stinging insects to which they are allergic (bees, yellow jackets, white faced hornets, yellow hornets, wasps, and in some areas of the country, fire ants). Most patients need to continue shots for 3-5 years. In addition, they should also carry a special self injecting Adrenalin pen (Epipen or Anakit) for emergencies.

Local Anesthetics

Patients who may be allergic to local anesthetics like Novocaine or Lidocaine can have skin testing done to determine if they are allergic. Most of the time the allergy is not to the local anesthetic but actually to the preservative contained in the anesthetic. It is usually possible to find at least one local anesthetic to which a patient is not allergic. Testing usually takes several hours and is similar to other allergy testing.

Antibiotic Allergy

Antibiotics can cause a variety of allergic symptoms including rashes, asthma, fever, and hives as well as more severe life threatening reactions. Patients who have reactions to antibiotics may need to have allergy tests to determine if they are allergic.

Allergy testing is only available for a limited number of antibiotics. The tests are similar to environmental testing, but may take several hours. If a patient is allergic, desensitization procedures have been developed which can be used if other appropriate antibiotics are unavailable.

Latex Allergy

Allergies to latex are becoming increasingly common for reasons that are unclear. Latex allergy was unknown prior to the late 1980's, but it is now estimated that 6% of people may be allergic to latex.

People have allergic reactions to natural latex such as rubber gloves, condoms, balloons,etc. Synthetic latex such as that used in paint is not a problem. People who are sensitive to some fruits, chestnuts,and hazelnuts may be more likely to be sensitive, as well as people with allergic rhinitis or hand dermatitis. This problem is also more common in patients with spina bifida (a rare medical problem) as well as in people who work in an operating room because of the amount of latex used there.

Symptoms typically include a rash, itching, swelling, asthma, hives, allergic rhinitis and can include more life threatening problems. They may occur anywhere from a few hours after exposure to a day later. Blood tests are available to test for latex allergy, but no skin test has been released by the FDA yet. People who have these kinds of reactions after a pelvic examination or a dental procedure may have latex sensitivity.

Even the dust from latex rubber gloves can cause problems. Just because something is labeled "hypoallergenic" doesn't mean that there is no latex. If you have problems with latex, it is very important to tell any physician or dentist who you see as they may use latex gloves, catheters and other medical items. There are non-latex gloves available. The problem for some people is so severe that there have been operating rooms developed that are latex-free.

A booklet on Latex allergy is available from 1-800-7ASTHMA.