• What is an allergy?
• Basic definitions
• Skin allergies
• Food allergies
• Insect allergies
• Medication allergies
• Occupational allergies
• Anaphylactic Shock

What is an allergy?

The immune system is a network of cells and organs that work together to defend the body against attacks by "foreign" invaders, or germs. The body provides an excellent environment for germs. When germs invade the body, it is the immune system's job to keep them out or to seek and destroy them.

When the immune system is malfunctioning it can cause a variety of diseases, such as allergy, arthritis, cancer or AIDS. The immune system is complex and sophisticated. It can recognize enemies and in most cases fight off the germ before we even know it has invaded our system. Anything that can trigger an immune response is called an antigen. When the immune system identifies a substance as harmful when in fact it is not, and attempts to destroy it, an allergic reaction has occurred. The misidentified substance is called an allergen.
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Basic definitions

Allergy: Allergy is an immunologically-mediated reaction to normally inert substances in the environment such as pollens, molds, pet dander, dust mites, foods and medications. The reaction is mediated by a type of antibody called IgE. The tendency to make IgE to substances is genetic and is inherited in families.

The term "allergies" is commonly applied to any adverse reaction to an external agent. In fact, many people are told they have allergies whenever something seems to be wrong and the cause is not clear. Most allergists are trained to diagnose and treat problems resulting from the IgE reaction as well as many that result from non-IgE mechanisms. Therefore, they are often able to help someone with a problem that is not allergy-mediated.

Healthwise: Allergic Reaction

Asthma: Asthma is a disease of the bronchial tubes caused by an inflammatory reaction in the lungs following the inhalation of irritating substances called "triggers." In response to a trigger, an asthmatic's airways become narrowed, inflamed and filled with excess mucus. Symptoms include wheezing, cough, shortness of breath, tightness in the chest, difficulty breathing during or after physical activity and waking up at night due to any of these symptoms.

Asthma affects more than 15 million Americans, including about five million children, and results in more than 5,000 deaths each year. It is caused by a sensitivity to certain allergens such as pollen, mold spores and dust mites, and may be irritated or aggravated by respiratory tract infections. Emotional stress can also trigger attacks, but stress is a secondary factor of a disease that is primarily allergic in nature.

Healthwise:

Asthma in Children

Asthma in Teens and Adults

Rhinitis: Rhinitis, or inflammation of the mucous membranes of the nose, is often classified simply as allergic or nonallergic rhinitis.

Allergic rhinitis, or "hay fever," affects more than 40 million Americans. It is caused by allergens such as weed, pollen, dust mites, mold or animal dander and may produce sneezing, congestion, runny nose, cough, shortness of breath, fatigue and itchiness in the nose, throat, eyes and ears. An allergist can provide more information on diagnosis and treatment.

Healthwise: Allergic rhinitis (hay fever)

Nonallergic rhinitis ("vasomotor" rhinitis, or "irritant" rhinitis) is a condition of unknown origin that seems to be aggravated by fumes, odors, temperature and atmospheric changes, smoke and other irritants. This form of rhinitis, which usually afflicts adults, causes year-round symptoms that include congestion and headache.

Sinusitis: Sinusitis is an inflammation of the nasal sinuses, which are hollow cavities within the bones found around and behind the nose. The inflammation is usually caused by inadequate draining of the sinuses due to allergy, infection or obstruction. Common symptoms include thick yellowish/green nasal discharge, headache, congestion, fatigue and fever.

In the 1993 National Health Interview Survey (NHIS), sinusitis was the most frequently reported chronic disease, affecting 14.7 percent of the population and accounting for 11.6 million physician visits per year.

There are two types of sinusitis. The first is acute sinusitis, which is caused by bacterial infection in most cases, and usually occurs as a late complication of a common cold. The second type is chronic sinusitis, which may be caused by bacterial infection, but more often is a chronic inflammatory disorder similar to bronchial asthma. Immunologic problems are another possible cause of chronic sinusitis.

Healthwise: Sinusitis

Hypersensitivity pneumonitis: Hypersensitivity pneumonitis is caused by exposure to various organic dusts, such as bird droppings, contaminated grain and feathers. Symptoms include fever, wheezing, chills and shortness of breath.
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Skin allergies

Atopic Dermatitis (eczema): also known as eczema, is an allergic skin condition which sometimes affects children and infants born to mothers who have an allergic disease.

Itching, sometimes intense, can lead to scabbing and flaking lesions. If bacterial or viral infection is introduced by scratching, the affected lesions ooze.

Healthwise: Atopic Dermatitis

Urticaria (hives): is different from atopic dermatitis as it is a side effect rather than a condition. Hives are red, very itchy, swollen areas of the skin, often appearing in clusters. Hives appear suddenly and may leave quickly in one to two hours, or can last as long as 24 hours. Approximately 20 percent of the population has suffered an eruption of hives at some point.

When hives are accompanied by swelling (angioedema) of the eyelids, tongue, mouth, hands or feet, difficulty in breathing or swallowing can occur.

Contact Dermatitis: produces rashes and itching after touching poison oak or ivy, certain foods or other substances.

Healthwise:

Rash, Age 11 and Younger

Rash, Age 12 and Older
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Food allergies

Allergies to certain foods, most notably fish, eggs, milk, nuts and wheat, induce intestinal disturbances, skin diseases and even anaphylactic shock (see below). They occur frequently in children, who often outgrow them after age three. Food intolerance, or an adverse reaction to certain foods, can cause bloating, diarrhea, nausea and vomiting, and is often mistaken for allergy. About 90% of patients seen in the PAMF Department of Allergy for a "food allergy" are actually intolerant of a specific food. PAMF allergists can help both the allergic and the food-intolerant patient.

Healthwise: Food Allergies
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Insect allergies

Allergic reactions to insect stings can cause a number of symptoms, ranging from local itching and swelling to anaphylactic shock (see below). Treatments for insect allergies include specific diagnostic testing and immunotherapy.

Healthwise: Allergies to Insect Stings
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Medication allergies

An allergist can help patients discern between intolerance to a specific medication and true medication allergies. Treatment includes diagnostic testing and, in some cases, desensitization to the drug through allergy shots.

Healthwise: Drug Allergies
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Occupational allergies

Occupational allergies are reactions to substances (usually inhaled) found on the job, such as chemicals, biomedical products and latex. PAMF allergists are trained in this relatively new field of allergy.
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Anaphylactic Shock

Anaphylactic shock is the most severe of all allergic reactions, causing swelling of body tissues (including the throat), vomiting, cramps and a sudden drop in blood pressure. Anaphylaxis often occurs in persons particularly sensitive to penicillin, stinging insects, shellfish or nuts.

Healthwise: Severe Allergic Reaction (anaphylaxis)
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