What is an Allergy?

An allergy is an abnormally high sensitivity reaction to an ordinarily harmless substance. The immune system of an "allergic person" reacts when an allergen is absorbed into their body, treating the substance as a harmful invader, causing the white blood cells to begin producing IgE antibodies which attach themselves to mast cells. When this occurs it causes the body to release histamine, which can cause allergy symptoms such as watery eyes, itching, sneezing or a runny nose.

When most people think of an allergy, they think of the sneezing, congestion, and itchy eyes caused by pollen. In fact, allergies can be caused by just about any substance that you inhale or swallow, or which touches your skin.

Your body's immune system is designed to attack harmful substances like bacteria and viruses. But with allergies, your body launches an assault on substances that are basically harmless -- such as pollen, mold, dust mites, pet saliva and dander, and even medications and insect sting venom. Allergies are extremely common. About 40% of the population suffers from them, leading to millions of missed work days and school days each year. Annual medical costs exceed $4 billion.

Not only do allergies cause a range of annoying symptoms such as sneezing and itchy eyes, but they can aggravate or trigger other conditions such as asthma, sinusitis, and ear infections. For example, when allergies cause inflammation in your nasal passages, the opening to your sinuses can become blocked, leading to sinus inflammation, sinus infections, and sinus pain. Similarly, if allergies cause inflammation in your ear canal, the ears don't drain properly, which can lead to ear infections.But allergies don't stop there. The body's immune system is active from your head to your toes: allergies can cause different skin-related symptoms (such as hives, eczema, and rashes); some types of allergies can lead to gastrointestinal problems; and assorted allergy-related symptoms can pervade the body (such as fatigue, headaches, loss of smell, and sleep disturbances).

One of the most deadly kinds of allergic reaction is called "anaphylaxis," which occurs when the entire body has a swift, severe reaction to something such as peanuts or bee stings. The body literally goes into shock, leading to a sharp drop in blood pressure, respiratory arrest, and possible heart failure.

What else is an Allergy?

When you react adversely to an environmental substance such as pollen, food or dust, you have an allergy but you can take comfort in knowing that you are not alone. Allergies affect approximately 40 million people in the United States. Ideally, the immune system creates antibodies that fight infections but an allergic person's body also produces antibodies against certain substances.

Are allergies hereditary?

Not all allergies are inherited but if you have a family history of allergies, your chance of becoming allergic is greater.

Do allergies begin in childhood?

Allergies can begin at any age, although many develop during childhood. In a few cases, allergies disappear on their own. Studies report that allergic children whose symptoms go untreated sometimes develop more serious symptoms later in life such as learning disorders, emotional problems, emphysema or asthma. Early diagnosis and treatment are the best ways to avoid these problems.

How are allergies diagnosed?

There are two tests primarily used to diagnose allergies. The first is the traditional skin prick test. It's performed by tiny scratches with specified allergens on your upper back and can usually be done during one visit. The second test is what's known as a RAST. This requires a blood sample to be drawn and tested in the laboratory. Once the allergy has been diagnosed, your physician will decide if the allergen can be avoided, or if treatment needs to be prescribed.Some people might misuse the term, "allergy" in an attempt to explain their intolerance of a food or drug. Lactose intolerant children may not be able to drink milk without extreme gastrointestinal upset, however this differs from an allergy. An allergic reaction would have the various symptoms listed above in addition to the upset stomach. A natural aversion to a food might signal an allergy. My son’s grandmother has been "peanut averse" all her life. She has never been tested for a peanut allergy, but very likely has some kind of allergy.

What constitutes a good allergy practitioner?

The Practitioner (doctor or nurse) needs to have plenty of time available for the consultation and a keen interest in allergy is paramount. In Allergology (the study of Allergy) the patient’s description of their allergy and careful questioning by the doctor goes 90% of the way to a correct diagnosis. This is usually followed by a brief examination of the relevant organs such as nose, eyes, lungs, glands and skin. Allergy tests should only be done to confirm the suspected allergy detected from the history. Tests should not be used as blind searches for an allergic component to the patient’s symptoms.

Once diagnosed, the patient needs to have the implications of their allergy explained to them in detail. They should be given some "easy to read" educational material to take home and digest. Understanding the nature and causes of the allergy will make future allergy control by the patient much more successful. A follow-up consultation is helpful as it provides an opportunity to discuss problems associated with the allergy and to reinforce the need for treatment.

What are those telltale signs that alert the doctor to probable allergy as the patient walks in the surgery door?

Allergic "shiners" are often a give-away – these are darkened areas of skin around the eye sockets, which are a result of increased venous congestion in the sinuses. They often resemble "Black Eyes" or look like "Mascara" around the eyes. There may be characteristic Dennie-Morgan infra-orbital folds or linear creases under the eyelids. The typical transverse nasal crease across the bridge of the nose is from constant nose itching and rubbing. The "allergic salute" is seen when the person’s hand constantly rubs the nose and is associated with facial grimacing or so called "Pulling of Faces" because the nose, eyes and ears are so itchy.

After many years of Nasal Allergy, the sufferer develops a so-called "Long Faced" appearance with constant open-mouth breathing, nose blockage, a high arched palate and dental malocclusion with "Buck Teeth".The allergy sufferer’s skin has a dry and rough sandpaper-like texture which is called Keratosis Pilaris. In children, this is commonly associated with eczematous rashes on the face, in the elbow creases and behind the knees. In adults Eczema tends to affect other areas such as the neck, wrists and back of hands.

The nose’s internal mucus membranes are usually swollen and oedematous with a pale blue appearance. The lower-eyelid conjunctival lining has a thickened "cobblestone" appearance and the eyes may be red, watery and itchy. Chronic middle ear mucus or "Glue ear" often accompanies nasal allergies. Other common allergic manifestations are a wheezy chest, constant sneezing, itchy watery eyes and "Nettle " rashes on the skin.