EMT Chapter 20: Allergic Reaction

List some of the more common causes of allergic reactions.

-Insect bites and stings from bees, yellow jackets, and wasps. -Foods such as nuts, eggs, shellfish, and milk. -Plants such as poison ivy, poison oak, and plant pollen. -Medications such as penicillin and other antibiotics. -Other things such as dust, chemicals, soaps, and makeup.

List signs or symptoms of an anaphylactic reaction associated with each of the following: -Skin -Respiratory system -Cardiovascular system

-Skin: itching; hives; red skin; swelling of the face; warm, tingling feeling in the face, mouth, chest, feet, and hands. -Respiratory system: tightness in the throat or chest; cough; rapid breathing; labored, noisy breathing; hoarseness, muffled voice, or loss of voice; stridor; wheezing. -Cardiovascular system: increased heart rate, decreased blood pressure.

List three actions (desired effects) of epinephrine when given for anaphylaxis:

1. Dilates the bronchioles 2. Constricts blood vessels 3. Makes the capillaries less permeable

What are the four most common categories of allergens?

1. Insects 2. Foods 3. Plants 4. Medications

List five skin signs associated with a severe allergic reaction:

1. Itching 2. Hives 3. Flushing (red skin) 4. Swelling of the face (especially the eyes and lips), neck, hands, feet, or tongue 5. Warm, tingling feeling in the face, mouth, chest, feet, and hands

A 10-year-old boy has developed a widespread rash after being stung by a bee. When gathering patient history, which of the following questions would be most important?

You should first ask the child if he has had any previous reaction to bee stings. If the answer is yes, then it is very likely that the current problem is associated with a severe allergic reaction. Past medical history is also relevant in that a history of asthma is associated with high mortality in allergic reactions; however, it is not as important as establishing a history of allergy. Last oral intake and last normal are also important but less specific to allergy.

epinephrine

a hormone produced by the body. As a medication, it constricts blood vessels and dilates respiratory passages and is used to relieve severe allergic reactions.

anaphylaxis

a severe or life-threatening allergic reaction in which the blood vessels dilate, causing a drop in blood pressure, and the tissues lining the respiratory system swell, interfering with the airway. Also called anaphylactic shock.

auto-injector

a syringe preloaded with medication that has a spring-loaded device that pushes the needle through the skin when the tip of the device is pressed firmly against the body.

allergic reaction

an exaggerated immune response.

What are the indications for administration of an epinephrine auto-injector?

patient exhibits the signs of an allergic reaction, medication is prescribed for the patient by a physician, and medical direction authorizes its use for the patient.

hives

red, itchy, possibly raised blotches on the skin that often result from allergic reactions.

allergen

something that causes an allergic reaction.

The red, itchy, possibly raised blotches on the skin associated with a severe allergic reaction are otherwise known as:

urticaria. Angioedema is swelling. Stridor is the high-pitched sound of partially obstructed air being forced through a swollen upper airway. Pruritis is itchy skin.

Which of the following signs is commonly associated with anaphylaxis?

Anaphylaxis is commonly associated with bronchoconstriction and therefore often produces wheezing. Gurgling represents fluid in the airway and is not usually caused by anaphylaxis. Rales are more commonly associated with pulmonary edema. A barking cough is usually associated with infection of the upper airway.

Which of the following substances are formed by the body's immune system in response to being exposed to a foreign substance?

Antibodies are formed by the body's immune system as a way of recognizing and fighting against a foreign substance; they are formed after the body is exposed to a particular substance for the first time. Antigens are simply foreign substances that cause an immune response. Allergens are foreign substances that elicit a more severe than normal immune response. Mast cells are specific cells in the connective tissue that break down in allergic reactions and release the chemicals that make the reaction happen.

Key Fact 4

By quickly recognizing the condition, consulting medical direction, and administering the appropriate treatment, you can literally make the difference between life and death for these patients.

Which of the following is an expected side effect of the administration of epinephrine?

Epinephrine causes a fight-or-flight response in the body and mirrors the effects of naturally occurring adrenaline. Consequently, you should expect the patient to become excitable and to experience tachycardia and vasoconstriction. Pallor is often a side effect of that vasoconstriction.

A 46-year-old female is severely nauseated after taking a prescription antibiotic for the first time. She notes she is feeling dizzy, and you assess her to be hypotensive. She tells you that she has never been exposed to this antibiotic before, so she cannot be allergic. You should:

Even though the patient has not been previously exposed, she can still be having a severe anaphylactoid reaction. The nausea and hypotension are prime indicators. In this case the symptoms are the same, but the reaction is not mediated by the same antibodies. You should immediately administer epinephrine.

A 10-year-old male is reporting difficulty breathing after accidently ingesting a cookie made with peanuts. He discloses a peanut allergy. You note his face appears swollen, and you hear wheezes. He does not have his epinephrine autoinjector, and you do not carry one. You should next:

Facial edema and wheezes indicate anaphylaxis. You should immediately initiate transport and intercept with ALS. Although albuterol may be helpful, you should not delay the time to the administration of epinephrine.

Please list side effects of epinephrine:

Increased heart rate, Pallor, Dizziness, Chest pain Headache, Nausea, Vomiting, Excitability, anxiety

Describe the pattern of vital sign changes associated with the onset of anaphylaxis:

Tachycardia, hypotension, tachypnea, and decreasing oxygen saturation

Key Fact 2

The most common symptom in all of these cases is itching. Patient with anaphylaxis, though, will also display life-threatening difficulty breathing and/or signs and symptoms of shock (hypoperfusion). These patients will also be extremely anxious. Their bodies are in trouble and are letting the patients know it.

Key Fact 3

The signs and symptoms of anaphylaxis are a result of physiological changes: vasodilation, bronchoconstriction, leaky capillaries, and thick mucus.

Your patient is a parent who came into his daughter's kindergarten class as a helper. After eating a cookie, he developed a funny feeling in his tongue that progressed to swelling. He is anxious and sweaty when you see him. His pulse is 126 and regular, respirations 32 and slightly labored, blood pressure 96/58, skin cool and moist, pupils equal and reactive to light.

This is a prime candidate for the epinephrine auto-injector. He has signs of airway compromise and shock. Follow local protocols to give the medication.

You are called to a 50 y/o woman who received a narcotic pain reliever after minor dental surgery. She believes she is allergic to some pain medication but can't remember which one. She has vomited twice. One time she believes she saw blood in her vomit. Her vital signs are pulse 92, strong and regular; respirations 22 and adequate, without wheezes or stridor; blood pressure 148/86; skin warm and dry; pupils equal and reactive to light.

This is not an anaphylactic reaction. Epinephrine is not appropriate at this time. Transport the patient and observe her for signs of allergic reaction.

Your twenty-four-year-old patient ate a meal that he believes contained shellfish. He is allergic to shrimp. While the kitchen staff rushes to determine if shrimp was used in or near the preparation of the patient's meal, you perform an examination. The patient is sweating and nervous. He appears to be breathing adequately. You do not note any wheezing or stridor. His face is slightly red. His pulse is 88, strong and regular; respirations 24; blood pressure 108/74; and skin warm and moist.

This patient does not have respiratory or circulatory compromise, but he may be on his way in that direction. His vital signs and adequate breathing indicate this is not the time to give epinephrine. However, the nature of shellfish allergies is that they can become severe. This is a good case to report to medical direction for advice.

A foreign substance that causes an allergic reaction is otherwise known as:

A foreign substance that causes an allergic reaction is otherwise known as an allergen. An antibody is a component of the immune system that helps identify known foreign substances. An antigen is simply a foreign substance that causes an immune response. It does not necessarily cause an allergic reaction. Mast cells are specific cells in the connective tissue that break down in allergic reactions and release the chemicals that make the reaction happen.

Key Fact 1

Allergic reactions are common. Anaphylaxis, a true life-threatening allergic reaction, is rare.

Anxiety is a common symptom in anaphylactic reactions, but anxiety alone can produce symptoms that resemble an anaphylactic reaction. What would be the effect of epinephrine on a person who appears to be having an anaphylactic reaction but is really having an anxiety attack with no anaphylaxis?

Any patients who are awake, whether they are experiencing an anaphylactic reaction or an anxiety attack, will experience similar effects from the administration of epinephrine. Remember that it's a very powerful drug that's primarily used in patients in cardiac arrest to try to save their lives. Using it in a conscious patient is very risky because it causes anxiety, difficulty breathing, rapid heart rate, palpitations, sweating, headache, nausea and vomiting, dizziness, and high blood pressure. However, you consider these side effects to be "acceptable trade-offs" when a patient is having anaphylaxis because of the life-threatening nature of the condition and the effectiveness of epinephrine in treating it. Administering epinephrine to a patient having an anxiety attack is a significant— and reportable—drug error.

Which of the following findings would more likely be associated with a minor allergic reaction as opposed to an anaphylactic reaction?

Localized swelling, that is, swelling that is limited to a small area, is a common sign of a minor allergic reaction. However, a widespread rash, a hoarse voice, and chest tightness are all signs of a more serious anaphylactic reaction.

Angioedema, or the swelling that occurs as a result of an allergic reaction, is caused primarily by:

Swelling associated with allergic reactions is primarily caused by fluid shifting out of leaky capillaries and occupying space in the extracellular space. Although vasodilation and increased blood flow do occur in an allergic reaction, it is most commonly the fluid shift that causes angioedema. Vasoconstriction is not usually associated with allergy.