Dr. Barry Dworkin

Originally published in The Ottawa Citizen April 15, 2003
Original Title: When to use an EpiPen

A recent pharmacist’s study presented to the Canadian Society of Allergy and Clinical Immunology indicates 63 per cent do not know how to use an EpiPen and 62.5 per cent cannot recognize the signs and symptoms of a severe allergic reaction (anaphylaxis).

Medications (penicillin, nonsteroidal anti-inflammatory drugs and aspirin, chemotherapy agents and angiotensin-converting enzyme inhibitors (ACEs)), bee and wasp stings, milk, seafood, nuts, blood transfusions, exercise and other chemical agents can trigger anaphylaxis.

The most common food allergies children develop in their first three years of life are to cow’s milk, peanuts, soy, eggs, shellfish and wheat. Peanuts, nuts and fish tend to be lifelong.

Two cell types, mast cells and basophils, are responsible for the allergic response. It is unknown why the response varies between people. Some develop a few hives or itchy skin whereas others develop a life threatening condition when the mast cells and basophils release abnormal quantities of chemical substances including histamine.

The blood vessels will dilate and leak fluid into the surrounding tissue causing swelling (angioedema) of the skin. Severe fluid loss leads to a collapse of the circulatory system.

The smooth muscle rings that encircle the airways (bronchi) will constrict. The airways themselves will produce copious amounts of mucous. The combination of these two effects plugs the airway making it impossible to breathe. Fluid can accumulate within the lungs leading to heart failure.

These and other reactions usually develop within five to 60 minutes after exposure. There can be a delay of one to eight hours before anaphylaxis occurs so vigilance is a priority.

The symptoms include:

• Itching, flushing, hives and swelling of the skin and sweating
• Itching, tearing and swelling of the tissues around the eyes
• Nasal congestion, runny nose, sneezing and a metallic taste in the mouth
• Difficulty breathing, wheezing, increased airway secretions and mucous production, swelling of the upper throat, blueness of the skin (cyanosis), hoarse voice, sounds of laboured breathing and a choking sensation
• Very rapid or very slow heart beat, an irregular heart beat, low blood pressure and cardiac arrest
• Nausea, vomiting, abdominal cramps, bloating and diarrhea
• Dizziness, weakness, fainting, a fear of impending doom and seizures
• Ninety per cent of people with allergic reactions have hives and skin swelling after feeling itchy, flushed and fearing impending doom.

Breathing difficulties occur in 50 per cent of these people especially those with asthma. Gastrointestinal symptoms and extremely low blood pressure (anaphylactic shock) occurs in 30 per cent.

Five to 20 per cent of people may have an initial allergic reaction that resolves but recurs one to eight hours later. Be on guard for this phenomenon. This happens when a person develops symptoms 30 minutes after exposure and in those orally ingesting the substance.

People at greatest risk of anaphylaxis have a history of asthma, eczema, allergic rhinitis (nasal allergies) and hives. Injection and intravenous administration of the allergen is likely to be more severe than if swallowed. Inhalation can provoke a response.

In the event of anaphylaxis, epinephrine will give you 15 to 20 minutes to get to an emergency room. Epinephrine counters the allergic response by constricting the blood vessels, relaxing the smooth muscle of the airways to improve breathing, stimulating the heartbeat, and reversing hives and swelling about the face and lips. Antihistamines will not reverse anaphylaxis fast enough to make a difference.

Emergency epinephrine provided in the EpiPen format is a spring-loaded syringe containing a pre-measured dose of epinephrine. A junior format is available for children weighing under 15 kilograms or 33 pounds.

To use the EpiPen follow these directions.

1. Slide the protective plastic sleeve off the unit
2. Remove the gray safety cap. Do not touch the black plastic tip.
3. With your dominant hand hold the EpiPen and position the black tip against the fleshy outer portion of the thigh. Keep all fingers clear of the black tip.
4. Push the pen against the thigh for five to ten seconds. Massage the area after the injection. Pain is minimal
5. A needle sticking out the end of the pen after you are done indicates proper delivery of the medication into the skin
6. Call 911 or seek emergency medical assistance.

You can inject through thin clothing if need be. View an animated version of EpiPen technique at www.epipen.com. The Calgary Allergy Network is another source of information (http://www.calgaryallergy.ca/Articles/epipen.html).

Your pharmacist can demonstrate how to use the EpiPen. An Ottawa company, Allergy Essentials (www.allergy-essentials.com) sells EpiPen trainers (fully functional without the needle for $6.50). Please take the few minutes to learn to save the time of your life.