This document defines anaphylaxis and hypersensitivity reactions, describes the pathophysiology and etiology of anaphylaxis, and outlines signs/symptoms, diagnosis, and treatment. It discusses how anaphylaxis is a severe allergic reaction affecting multiple organ systems. Common triggers include foods, medications, insect bites, and latex. Diagnosis is based on symptoms occurring rapidly after exposure. Treatment involves epinephrine, antihistamines, corticosteroids, bronchodilators, and emergency management including CPR if needed.

1. ANAPHYLAXIS
Dr. Virendra Kumar Gupta
Assistant Professor
Department Of Pediatric Gastroentero-hepatology &
Liver Transplantation
NIMS Medical College & Hospital , Jaipur

2. Objectives
 Define Hypersensitivity Reaction.
 Mention the Types of Hypersensitivity
Reactions.
 Define Anaphylaxis.
 Mention the Etiologic Causes.
 Explain the Pathophysiologic Mechanism.
 Mention the Signs & Symptoms.
 Demonstrate the Diagnostic Investigations.
 Display the Treatment & First Aid.

3. Hypersensitivity Reaction
 Injurious, or pathologic, immune reactions are
called hypersensitivity reactions.
 Hypersensitivity reactions may occur in two
situations.
 First, responses to foreign antigens may be
dysregulated or uncontrolled, resulting in
tissue injury.
 Second, the immune responses may be
directed against self antigens, as a result of
the failure of self-tolerance (autoimmunity).

4. Types of hyper sensitivity
reactions
• Type I
• IgE Mediated
• Classic Allergy
Immediate
hypersensitivity
• Type II
• IgG/IgM
• Mediated
• RBC lysis
Antibody-
mediated
• Type III
• IgG Mediated
• Immune complex
Disease
• Serum Sickness
immune complex
diseases
• Type IV
• T cell
• Delayed Type
Hypersensitivity
T cell-mediated
diseases

5. Anaphylaxis
 Ana (without), phylaxis (protection).
 Anaphylaxis is a sudden, severe allergic reaction that can be
life-threatening.
 It can occur within seconds or minutes of exposure to
something someone is allergic to
 IgE-mediated (type I) hypersensitivity reaction resulting in the
release of potent chemical mediators
 Mast Cells
 Basophils
 Affects multiple organ systems
 Respiratory
 Cardiovascular
 Gastrointestinal
 Dermatologic
 Clinical Diagnosis
 Biphasic Reactions

6. Clinical
Definition

7. clinical criteria
 Any one of the following three occurs within minutes/hours of exposure
to an allergen there is a high likelihood of anaphylaxis:
1. Involvement of the skin or mucosal tissue plus either respiratory
difficulty or hypotension.
2. Two or more of the following symptoms:
a. Involvement of the skin or mucosa
b. Respiratory difficulties
c. Low blood pressure
d. Gastrointestinal symptom
3. Low blood pressure after exposure to a known allergy.

8. Etiology
34%
37%
20%
7%
2%
Causes of anaphylaxis in a study of 266 patients (Data
from Kemp et al)
Food
Idiopathic
Drugs
Exercise
Latex, hormons,
insect bites

9. Etiology
Pharmlogic agents
• Antibiotics (penicillin)
• Nonsteroidal anti-inflammatory drugs (Asprin)
• intravenous (IV) contrast agents
Stinging insects
• Ants, bees, hornets, wasps, and yellow jackets.
Food
• Peanuts, seafood, and wheat
• Milk, soy, eggs
Latex
• Rare
• No latex-associated deaths

10. Pathophysiology

11. Pathophysiology
Mediators
Vascoactive aminase &
lipid
Immediate
hypersensitivity reaction
(minutes)
Cytokines
Late phase reaction (6-
24 hours)

12. Signs & Symptoms
Itching flushing
hives (urticaria) swelling
Skin

13. Signs & Symptoms
Itching tearing
redness
swelling around the
eyes
Eyes

14. Signs & Symptoms
Sneezing
runny nose nasal congestion
swelling of the
tongue
metallic taste
Nose &
mouth

15. Signs & Symptoms
Difficulty breathing coughing chest tightness
wheezing or other
sounds
increased mucus
production
throat swelling or
itching
change in voice
or a sensation of
choking
Lungs and
throat

16. Signs & Symptoms
Dizziness weakness fainting
rapid, slow, or
irregular heart rate
low blood pressure
Heart and circulation

17. Signs & Symptoms
Nausea vomiting
cramps diarrhea
Digestive system

18. Signs & symptoms
Anxiety confusion
sense of impending
doom
Nervous system

19. Diagnosis
 The diagnosis of anaphylaxis is based upon symptoms
that occur suddenly after being exposed to a potential
trigger.
 Differential diagnosis
 severe asthma attack
 heart attack
 panic attack
 food poisoning
 An increased amount of tryptase protein can be
measured in a blood sample collected during the first
three hours after anaphylaxis symptoms have begun.
 tryptase levels are seldom elevated in food-induced

20. First-Aid management of
anaphylaxis
 1. Seek emergency care
 Call for help
 2. Inject Epinephrine Immediately
 Inject epinephrine into outer muscle of the
thigh.
 3. Do CPR if the Person Stops Breathing

21. First Aid
Place patient in
Trendelenburg
position.
Establish and
maintain airway.
Give oxygen via
nasal cannula as
needed.
Place a tourniquet
above the reaction
site.
Epinephrine at the
site of antigen
injection.
Start IV to rise BP.

22. groups of drugs used
 Epinephrine: help maintain blood pressure,
antagonize effects of released mediators, and
prevent further release of mediators.
 Antihistamines (Diphenhydramine,
Hydroxyzine): primarily effective against
cutaneous effects of anaphylaxis.
 H2 Receptor Antagonists (Cimetidine): block
effects of released histamine at H2 receptors,
thereby treating vasodilation.
 Bronchodilators (Albuterol): These agents
stimulate beta2-adrenergic receptors in bronchial
smooth muscle, causing bronchodilation.

23. Prevention
Avoid the responsible allergen (e.g.
food, drug, latex, etc.).
Keep an adrenaline kit (e.g. Epipen) and
Benadryl on hand at all times.
Wear medic Alert bracelets .
Venom immunotherapy is highly effective in
protecting insect-allergic individuals.

24. Question 1
A 5 year old M who has experienced a severe
allergic reaction to shrimp in the past needs a
CT scan with IV and oral contrast. What
precautions should you take?
A. NS bolus and diphenhydramine
B. NS bolus, diphenhydramine, and prednisone
C. This patient can not receive contrast
D. Reassurance, there is no associated risk for a
reaction between shellfish and contrast

25. Question 1
A 5 year old M who has experienced a severe
allergic reaction to shrimp in the past needs a
CT scan with IV and oral contrast. What
precautions should you take?
A. NS bolus and diphenhydramine
B. NS bolus, diphenhydramine, and prednisone
C. This patient can not receive contrast.
D. Reassurance, there is no associated risk for
a reaction between shellfish and contrast.

26. Question 2
You have been asked by a local school to provide
recommendations about the use of self injectable
epinephrine for anaphylaxis. What is the BEST
response to give regarding anaphylaxis?
A. A patient should not receive a second dose of
epinephrine unless a physician is present
B. Epinephrine reaches higher peak plasma
concentrations in injected into the thigh rather than
the arm
C. Families should keep one epinephrine auto injector in
the car in case a reaction occurs after school
D. Subcutaneous injection of epinephrine is preferable
to intramuscular injection

27. Question 2
You have been asked by a local school to provide
recommendations about the use of self injectable
epinephrine for anaphylaxis. What is the BEST
response to give regarding anaphylaxis?
A. A patient should not receive a second dose of
epinephrine unless a physician is present
B. Epinephrine reaches higher peak plasma
concentrations in injected into the thigh rather
than the arm
C. Families should keep one epinephrine auto injector in
the car in case a reaction occurs after school
D. Subcutaneous injection of epinephrine is preferable
to intramuscular injection

28. Question 3
A 14 y/o M who has seasonal allergies and moderate
persistent asthma is currently receiving allergen
immunotherapy. Today in clinic he received his usual
allergen injection, but after 10 minutes, he started
coughing and complaining of dyspnea and throat
swelling. On physical exam he exhibits moderate
respiratory distress and has diffuse expiratory
wheezing on auscultation. No oropharyngeal edema
noted. Vitals signs include a pulse ox of 97%, BP of
130/70, and HR of 90. Of the following, the MOST
appropriate next action is to administer:
A. A short acting beta-2 agonist nebulization
B. An oral antihistamine
C. An oral corticosteroid
D. Intramuscular epinephrine

29. Question 3
A 14 y/o M who has seasonal allergies and moderate
persistent asthma is currently receiving allergen
immunotherapy. Today in clinic he received his usual
allergen injection, but after 10 minutes, he started
coughing and complaining of dyspnea and throat
swelling. On physical exam he exhibits moderate
respiratory distress and has diffuse expiratory
wheezing on auscultation. No oropharyngeal edema
noted. Vitals signs include a pulse ox of 97%, BP of
130/70, and HR of 90. Of the following, the MOST
appropriate next action is to administer:
A. A short acting beta-2 agonist nebulization
B. An oral antihistamine
C. An oral corticosteroid
D. Intramuscular epinephrine

30. Question 4
A 10 y/o M with a history of peanut allergy presents with diffuse itching
and trouble breathing after eating a friend’s candy bar that contained
nuts during school lunch. At the nurse’s office the patient received IM
epinephrine with his EpiPen with symptom resolution. EMS was called
and the patient was brought to the local pediatric ED (about a 12
minute ride). On arrival to the ED, the patient is again complaining of
itching with an urticarial rash on his chest and per EMS the patient
began vomiting as they were pulling up to the ambulance bay. Arrival
vitals include a pulse ox of 96%, BP of 88/67, and HR of 95. Of the
following, the MOST appropriate treatment plan is:
A. Intramuscular epinephrine, oral antihistamine, oral corticosteroid,
and a short acting beta-2 agonist neb treatment
B. Intramuscular epinephrine, IV antihistamine, IV corticosteroid, NS
bolus
C. Intramuscular epinephrine, IV antihistamine, IV Zantac, NS bolus

31. Question 4
A 10 y/o M with a history of peanut allergy presents with diffuse itching
and trouble breathing after eating a friend’s candy bar that contained
nuts during school lunch. At the nurse’s office the patient received IM
epinephrine with his EpiPen with symptom resolution. EMS was called
and the patient was brought to the local pediatric ED (about a 12
minute ride). On arrival to the ED, the patient is again complaining of
itching with an urticarial rash on his chest and per EMS the patient
began vomiting as they were pulling up to the ambulance bay. Arrival
vitals include a pulse ox of 96%, BP of 88/67, and HR of 95. Of the
following, the MOST appropriate treatment plan is:
A. Intramuscular epinephrine, oral antihistamine, oral corticosteroid,
and a short acting beta-2 agonist neb treatment
B. Intramuscular epinephrine, IV antihistamine, IV corticosteroid, NS
bolus
C. Intramuscular epinephrine, IV antihistamine, IV Zantac, NS bolus

32. Thank You