Tendency Toward
Allergic Reactions

Allergies are an overreaction of the body's natural defense system that helps fight infections.

An allergic reaction may not occur the first time you are exposed to an allergen, but then occur on subsequent exposures.  There are many types of allergies, including:

• food allergies
• allergies to medicines
• allergies to venom (insect, reptile, etc.)
• allergies to animals – dead skin (dander), urine, dried saliva, or hair
• allergies to natural rubber (latex)
• allergies to inhaled substances
• allergies to cosmetics or other substances applied to the skin such as henna tattoos
• seasonal allergies caused by exposure to pollens.  Hay fever is the most common seasonal allergy.

Incidence; Causes and Development; Contributing Risk Factors

The American Academy of Allergy, Asthma & Immunology reports that as many as 1-in-6 people in the United States suffer from some type of allergic disease.

During allergic reactions, the immune system starts fighting substances that are usually harmless (for example dust mites, pollen, or a type of food) as though these substances were trying to attack the body.  This overreaction causes allergy symptoms such as rash, itchy eyes, a runny nose, trouble breathing, nausea, or diarrhea.

Allergens that cause a reaction can come in contact with the skin, be inhaled, or be eaten.  People who have allergies are typically allergic to one or more of the following:

• pet dander
• bee stings or bites from other insects
• certain foods, including nuts or shellfish
• certain medications such as penicillin or aspirin
• certain plants
• pollen

If you have a close family member who has allergies, you will have a greater risk for developing allergies.

Signs and Symptoms

The symptoms of allergic reactions can be mild or severe.  Symptoms may worsen upon repeated exposure.

Mild symptoms can include:

• hives
• itching
• nasal congestion
• a rash
• watery or itchy eyes

Severe reactions can include:

• abdominal cramping or pain
• pain or tightness in the chest
• diarrhea
• difficulty swallowing
• dizziness / vertigo
• fear or anxiety
• facial flushing
• nausea or vomiting
• heart palpitations
• swelling of the face, eyes, or tongue
• weakness
• wheezing
• difficulty breathing
• unconsciousness

Diagnosis and Tests

The most common types of allergy tests are:

• Skin tests to observe any reaction to substances applied to the skin
• Challenge (elimination-type) tests
• Blood tests to look for antibodies against certain allergens

Treatment and Prevention

Allergens can be used to diagnose allergies and even be injected as form of treatment.

Complications; Seek medical attention if...

Most allergic reactions are mild, but a severe allergic reaction (anaphylaxis) is more serious.  Anaphylaxis can develop within seconds of being exposed to an allergen and cause a variety of problems ranging from nosebleeds or coughing... to swelling of the airway, an inability to breathe, or a dramatic drop in blood pressure... to death.

If you experience symptoms of anaphylaxis, seek immediate emergency help.  Without treatment, anaphylaxis can result in death within 15 minutes.