The Bottom Line
Allergy
problems are extremely prevalent in the United States. The American Academy of
Otolaryngic Allergy (AAOA) estimates that allergies significantly affect about
50 million Americans, and allergies represent some of the most common types of
chronic illness in the US. Allergy issues can range from seasonal allergies,
such as allergic reactions to certain types of pollen, to environmental
allergies like problems with pet dander and dust mites. Allergic responses to
insect stings, like bee venom, can also be severe and even life-threatening.
Types of Allergies
There are
several common types of allergies, classified according to the kind of allergen
or substance that triggers the allergy. These allergy types include:
Seasonal
allergies – This type of allergy is triggered by exposure to pollen. As the
name implies, seasonal allergies are usually limited to one or two seasons of
the year. For example, ragweed pollen is a frequent cause of seasonal fall
allergies, and pollen from trees is often the source of spring and seasonal summer
allergies. Seasonal allergies are usually minimized in the winter due to low
pollen counts.
Mold allergies
– Many species of mold can trigger allergies. These species include Penicillium, Aspergillus, and Alternaria.
While it is possible to suffer mold allergies from outdoor exposure, most mold
allergy cases occur from indoor exposure due to a higher concentration of mold
spores.
Insect
allergies – Insect stings can be painful and annoying for anyone, but around 5
– 7.5% of the population suffers from allergic reactions to bee, wasp, yellow
jacket, and other insect stings. The severity of reactions ranges from intense
swelling and discomfort near the site of the sting to difficulty breathing,
which may lead to death without immediate treatment.
Food allergies
– Allergies to certain foods have increased in recent decades. The most common
foods that cause allergic reactions include cow’s milk, shellfish, tree nuts,
peanuts, and eggs.
Latex allergies
– Latex is a type of rubber frequently used in healthcare. Latex allergies are
most common in healthcare workers who experience frequent exposure to latex
gloves and other latex products.
Environmental
allergies – This is a broad group of allergies that can include mold allergies
as well as allergies to animal dander, dust mites, and other irritants.
Allergy Symptoms
Allergy
symptoms vary according to the type of allergy. A runny nose, watery and red
eyes, sneezing, coughing, and congestion are the hallmarks of seasonal, mold,
and environmental allergies. If allowed to continue, these symptoms may worsen
into a case of sinusitis or bronchitis.
An allergic
reaction to certain foods usually manifests as stomach upset, diarrhea, and
nausea and vomiting. In addition to these gastrointestinal symptoms, food
allergies can cause hives, itching of the mouth and skin, and facial and throat
swelling. A latex allergy also causes a localized reaction of hives and itching
along with swelling and sometimes a runny nose.
An allergic
reaction to an insect sting will cause swelling at the site of the sting and
may also cause swelling in other parts of the body. Insect allergies may also
result in hives, flushing, redness of the skin, and anaphylaxis.
Anaphylaxis
In certain
individuals, food, insect, and latex allergies can lead to a condition called
anaphylaxis. Anaphylaxis is potentially life-threatening and constitutes an
extreme medical emergency. Characteristics of anaphylaxis include swelling of
the throat and face, skin reactions like hives and flushing, difficulty
breathing, fainting and dizziness, low blood pressure, and a rapid pulse.
Anaphylaxis requires an immediate injection of epinephrine, also called
adrenaline, and professional medical attention.
What Causes Allergies?
An inappropriate
immune response is the source of allergy symptoms. Specifically, a foreign
substance like wasp venom or pollen triggers the immune system. The immune
system identifies this foreign substance as an invasive microorganism like
bacteria or a virus. In turn, the immune system produces antibodies and other
factors that cause inflammation.
In reality,
allergens do not pose a major threat to the body. It is the immune system’s
overblown response to allergens that causes allergy symptoms from a mildly
runny nose to deadly anaphylaxis.
Risk Factors
Allergies can
strike anyone. However, there are a few risk factors that can make an
individual more likely to experience allergies.
Family history
– A family history of allergies or related conditions such as hives, asthma,
and eczema may increase the likelihood of allergy problems.
Age – Children
are more likely to experience allergies than adults. Sometimes children will
“grow out” of childhood allergies as they mature.
Frequent
exposure – Repeated and prolonged exposure to certain allergens can cause
allergies to develop. For example, healthcare workers who often wear latex
gloves may develop a latex allergy. Similarly, beekeepers have a higher rate of
bee sting allergies than the general population.
Preventing Allergies
Once allergies
surface, avoidance of allergens is among the most effective measures to prevent
allergy symptoms. For instance, being careful concerning a diet is important
for those with food allergies. Likewise, wearing good quality filter masks when
doing yard work and taking measures to limit exposure to outside air may help
significantly with seasonal allergies.
Lifestyle
changes are sometimes necessary to control allergies. Those with allergies to
cat dander may need to consider a different choice of pet, for example. Also,
latex allergy triggers can be avoided by switching to a different material,
like nitrile protective gloves.
Of course,
avoidance is not always possible. Those with severe allergies need to be
prepared. Individuals who suffer from severe allergic reactions should always
carry an epinephrine delivery device (brand names include EpiPen and Adrenaclick)
and a medical identification alert. They should also ensure that those close to
them are aware of their allergy and the symptoms of anaphylaxis. Fortunately,
there are also desensitization immunotherapy treatments available for some
types of allergies, discussed in the section below.
Allergy Treatment
In the case of
mild seasonal or environmental allergies, over-the-counter medications are
often sufficient to control symptoms. Effective medications include
antihistamines for nasal symptoms and cortisone creams for skin problems.
Symptoms of moderate severity may require prescription medications such as
corticosteroids.
When allergy
symptoms are severe or interfere with daily life and avoidance of triggers is
not feasible, allergy testing and immunotherapy can be quite beneficial.
Doctors perform allergy testing to identify the specific allergens causing the
symptoms. A patient may only know that they develop allergy symptoms during the
spring. They may not realize that oak tree pollen is the offending substance.
Allergy testing pinpoints the problem while eliminating other potential causes.
Allergy testing
can be done in several ways. The modified quantitative testing (MQT) protocol
is an allergy diagnostic that is dependable, minimally invasive, and proven
safe. This protocol is a combination of skin prick testing and intradermal
testing (IDT) that is quite comfortable and causes no pain. Ear, nose, and
throat (ENT) specialists use MQT to identify moderate to severe allergies. MQT
can be performed safely in-office and does not require a hospital visit.
Blood testing
for allergies, called RAST, may be an option for individuals who have severe
skin conditions, take medications that interfere with MQT testing, or are
otherwise not good candidates for the MQT protocol. RAST testing involves a
simple blood draw. The blood sample is analyzed in a laboratory, and the
results are provided to the ENT physician.
Immunotherapy,
commonly called allergy shots, can often be done when more conservative
measures like allergen avoidance and medications have failed. Immunotherapy
involves injecting minute amounts of an allergen to desensitize the immune
system to that allergen.
Only certain
types of allergies respond to immunotherapy. Unfortunately, food allergies and
latex allergies cannot currently be controlled through immunotherapy. However,
insect, environmental, and seasonal allergies often show good responses to
immunotherapy treatments. For instance, about 85% of people experience
excellent results from immunotherapy for hayfever (allergic rhinitis).
In
immunotherapy, the ENT creates a customized vial for each patient. The vial
contains a mixture of allergens to which testing has demonstrated the patient
has a sensitivity. The patient receives an injection each week, gradually
advancing the dose at a safe rate. Over time, this treatment will cause the immune
system to create antibodies to the offending allergens. Ultimately, immunotherapy
will result in immunity to the offending allergen, and the patient will have no
symptoms when they are around the allergen.
Typically, in
our practice, we perform a four-month trial of immunotherapy, and if there is a
significant reduction in symptoms, we will continue with the full course of
immunotherapy. The course consists of injections weekly for the first year,
twice monthly for the second year, and monthly for the last year. Over-the-counter
and prescription allergy medications only help to mask the symptoms of
allergies. Immunotherapy is the only method of actually eliminating symptoms by
acclimating the body to allergens and stimulating antibody production.
Immunotherapy
through desensitization injections can allow allergy sufferers to experience a
greatly improved quality of life. Often, they are able to enjoy the outdoors
again and are no longer limited by their symptoms. In the case of insect
allergies, immunotherapy can even be potentially lifesaving.