Anaphylaxis: Difference between revisions
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{{Adult top}} [[Anaphylaxis (peds)]].'' | |||
==Background== | ==Background== | ||
*Type I [[Hypersensitivity Reaction|hypersensitivity reaction]] | *Type I [[Hypersensitivity Reaction|hypersensitivity reaction]] that is either severe in nature or having two or more organ systems involved. | ||
*Clinically [[Anaphylaxis]] and its treatment is virtually identical whether it is the traditional IgE dependent anaphylaxis reaction (vast majority), or the IgE independent ''anaphylactoid'' reaction | *Clinically [[Anaphylaxis]] and its treatment is virtually identical whether it is the traditional IgE dependent anaphylaxis reaction (vast majority), or the IgE independent ''anaphylactoid'' reaction | ||
*Precipitants | |||
**Food (most common) | |||
**Medications | |||
**Insect stings | |||
**Latex | |||
**Aerobic exercise | |||
**Idiopathic (rare) | |||
==Clinical Features== | ==Clinical Features== | ||
[[File:Hives2010.jpg|thumbnail|Raised [[urticaria]]]] | [[File:Hives2010.jpg|thumbnail|Raised [[urticaria]]]] | ||
[[File:1440px-Rash on the chest of a person with anaphylaxis.jpg|thumb|Urticarial rash on the chest of a patient with anaphylaxis.]] | |||
[[File:Angioedema2013.jpg|thumbnail|[[Angioedema]] of tongue]] | [[File:Angioedema2013.jpg|thumbnail|[[Angioedema]] of tongue]] | ||
[[File:Angioedema2010.jpg|thumb|Angioedema of face.]] | |||
*Cutaneous symptoms (90%) | *Cutaneous symptoms (90%) | ||
**[[Hives]] | **[[Hives]] | ||
**[[Angioedema]] | **[[Angioedema]] | ||
**Itching | |||
**Morbilliform rash | |||
*Respiratory symptoms (70%) | *Respiratory symptoms (70%) | ||
**[[Wheezing]] | **[[Wheezing]] | ||
**[[Shortness of breath]] | **[[Shortness of breath]] | ||
**Throat itching or tightness | |||
**Hoarseness | |||
**Stridor | |||
**Hypoxia, cyanosis | |||
*Gastrointestinal symptoms (40%) | *Gastrointestinal symptoms (40%) | ||
**Abdominal pain | |||
**Nausea, vomiting | |||
**[[Diarrhea]] | **[[Diarrhea]] | ||
*Cardiovascular symptoms (35%) | *Cardiovascular symptoms (35%) | ||
**[[Hypotension]] | **[[Hypotension]] | ||
**Chest pain | |||
**Palpitations | |||
*Central Nervous System | |||
**Uneasiness | |||
**Altered mental status | |||
**Headache, dizziness, confusion | |||
**Syncope | |||
===Expected Course=== | ===Expected Course=== | ||
| Line 24: | Line 49: | ||
*Uniphasic response, followed by asymptomatic period of hour or more, then return of symptoms | *Uniphasic response, followed by asymptomatic period of hour or more, then return of symptoms | ||
*The second phase does not necessarily resemble the first! | *The second phase does not necessarily resemble the first! | ||
*More likely with a severe initial presentation, | *More likely with a severe initial presentation or repeated epinephrine doses. Additionally hypotension, widened pulse pressure, unknown trigger, and drug trigger in children<ref>Ellis AK, Day JH: Incidence and characteristics of biphasic anaphylaxis: A prospective evaluation of 103 patients. Ann Allergy Asthma Immunology. 2007; 98:64-69</ref><ref name="aaaai"/> | ||
*Little evidence to support the use of discharge steroids to prevent a biphasic reaction | *Little evidence to support the use of discharge steroids to prevent a biphasic reaction | ||
*0.4% of patients with anaphylaxis had a rebound event while in the ED<ref name="biphasic"/> | *0.4% of patients with anaphylaxis had a rebound event while in the ED<ref name="biphasic"/> | ||
| Line 42: | Line 67: | ||
===Criterion 2 (10-20% of patients)=== | ===Criterion 2 (10-20% of patients)=== | ||
*TWO OR MORE of the following | *TWO OR MORE of the following that occur rapidly after exposure to a LIKELY allergen for that patient | ||
**Involvement of the skin-mucosal tissue (hives, swollen lips-tongue-uvula) | **Involvement of the skin-mucosal tissue (hives, swollen lips-tongue-uvula) | ||
**Respiratory compromise | **Respiratory compromise | ||
| Line 57: | Line 82: | ||
==Management== | ==Management== | ||
*'''[[Epinephrine]]''' | |||
**1:1000 '''IM''' 0.3 - 0.5mg (0.3 - 0.5mL) every 5 - 15 minutes <ref>Dhami S. et al. Management of anaphylaxis: a systematic review. Allergy. 69 (2014) 168–175. http://onlinelibrary.wiley.com/store/10.1111/all.12318/asset/all12318.pdf?v=1&t=hrspdbpk&s=8067bfd5903c7ffebf4a274f062a71633ebe0507</ref> <ref>Sheikh A, Shehata YA, Brown SGA, Simons FER. '''Adrenaline (epinephrine) for the treatment of anaphylaxis with and without shock.''' ''Cochrane Database of Systematic Reviews'' 2008, Issue 4. Art. No.: CD006312. DOI:10.1002/14651858.CD006312.pub2</ref> | |||
***0.5mg for adults >50kg is strongly associated with a reduction in escalation of care <ref>Retrospective comparison between 0.3 mg and 0.5 mg dosing of intramuscular epinephrine for anaphylaxis. Am J Emerg Med. 2025 Oct 10;99:270-275. doi: 10.1016/j.ajem.2025.10.020. </ref> | |||
**Intramuscular injection of epinephrine into the thigh as the preferred route and site of injection <ref>Simons FER, Gu X, Simons KJ. '''[[Epinephrine]]absorption in adults: Intramuscular versus subcutaneous injection,''' ''J Allergy Clin Immunol'' 2001;108:871-3 </ref> <ref>Epinephrine absorption in adults: Intramuscular versus subcutaneous injection. Simons, F.Estelle R. et al. Journal of Allergy and Clinical Immunology, Volume 108, Issue 5, 871 - 873 </ref> | |||
**If response to IM is inadequate: give epinephrine infusion 1:10,000 2 - 10 µg/min | |||
**'''How to make a quick epinephrine drip:''' ''Take your code-cart epinephrine (it does not matter if it is 1:1,000 or 1:10,000) and inject 1mg into a liter bag of NS. Final concentration is 1mcg/ml. Run at 1cc/min and titrate to effect''. | |||
*'''[[Corticosteroids]]''' | |||
**[[Methylprednisolone]]: 125mg IV (2mg/kg in children) | |||
**[[Dexamethasone]]: 10mg IV or PO (0.6mg/kg in children) | |||
**Evidence: | |||
***May start having effect within 5-30 minutes<ref>Liyanage CK, et al. Corticosteroids in management of anaphylaxis; a systematic review of evidence. Eur Ann AllErgy Clin immunol. 2017. 49(5): 196-207. 10.23822/EurAnnACI.1764-1489.15.</ref> | |||
***Appears to reduce the length of hospital stay.<ref>Liyanage CK, et al. Corticosteroids in management of anaphylaxis; a systematic review of evidence. Eur Ann AllErgy Clin immunol. 2017. 49(5): 196-207. 10.23822/EurAnnACI.1764-1489.15.</ref> | |||
***While there is no compelling evidence to support or oppose, use appears beneficial and there is no evidence of adverse outcomes related to use.<ref>Liyanage CK, et al. Corticosteroids in management of anaphylaxis; a systematic review of evidence. Eur Ann AllErgy Clin immunol. 2017. 49(5): 196-207. 10.23822/EurAnnACI.1764-1489.15.</ref> | |||
*'''Supplemental oxygen''' | |||
**''Consider [[Intubation|endotracheal intubation]] if airway edema present'' | |||
*'''Normal saline bolus''' | |||
**If unresponsive to [[epinephrine]] assume distributive [[Shock|shock]] and give 1 - 2 liters of normal saline | |||
*'''Also consider''' | |||
**[[Albuterol]] for bronchospasm resistant to IM epinephrine | |||
**[[Antihistamines]] (for symptom control AFTER hemodynamically stable) | |||
***[[Diphenhydramine]]: 25 to 50mg IV (1mg/kg in children) | |||
***[[Ranitidine]]: 50mg IV (0.5mg/kg in children) (has been found to improve urticaria but not angioedema at 2 hours<ref>Lin, RY et al. Improved Outcomes in Patients With Acute Allergic Syndromes Who Are Treated With Combined H1 and H2 Antagonists. Annals of Emergency Medicine. 36:5 NOVEMBER 2000.</ref>) | |||
***[[Cetirizine]] 10mg IV (6-11 years old: 5-10 mg IV; 6 mo - 5 years: 2.5 mg IV) | |||
***AVOID promethazine as this can worsen hypotension | |||
**[[Glucagon]] | |||
***1 - 5mg IV over 5 minutes followed by infusion of 5 - 15 µg/min<ref>Campbell RL, et al. Emergency department diagnosis and treatment of anaphylaxis: a practice parameter. Ann Allergy Asthma Immunol. 2014; 113:599e608.</ref> | |||
***If taking beta-blocker AND unresponsive to [[Epi|epinephrine]] | |||
**Consider adding additional pressor support if persistent hypotension present | |||
***For example: '''[[vasopressin]]''' 2-8 units for persistent refractory shock (case series only)<ref>Schummer et al. The Pivotal Role of Vasopressin in Refractory Anaphylactic Shock. Anesthesia & Analgesia: August 2008 - Volume 107 - Issue 2 - pp 620-624.</ref><ref>Dünser et al. Treatment of Anaphylactic Shock: Where Is the Evidence? Anesthesia & Analgesia: August 2008 - Volume 107 - Issue 2 - pp 359-361</ref> | |||
***[[Norepinephrine]] 0.05 to 0.5 mcg/kg per minute | |||
==Disposition== | ==Disposition== | ||
===Admit=== | ===Admit=== | ||
*Severe and moderate presentations especially if symptoms did not respond promptly to epinephrine or required repeat dosing | *Severe and moderate presentations, especially if symptoms did not respond promptly to epinephrine or required repeat dosing | ||
*Labs that may be requested by allergist/admitting team if uncertain diagnosis | *Labs that may be requested by allergist/admitting team if uncertain diagnosis | ||
**Histamine level - serum elevation 30-60 min following anaphylaxis, window easily missed | **Histamine level - serum elevation 30-60 min following anaphylaxis, window easily missed | ||
| Line 94: | Line 121: | ||
===Discharge=== | ===Discharge=== | ||
* | *Consider discharge after 1 hour observation, if no severe symptoms and no repeat epinephrine doses (AAAAI recommendations)<ref name="aaaai">Shaker MS, Wallace DV, Golden DBK, et al. Anaphylaxis-a 2020 practice parameter update, systematic review, and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) analysis. J Allergy Clin Immunol 2020; 145:1082. https://www.aaaai.org/Aaaai/media/Media-Library-PDFs/Professional%20Education/Podcasts/Anaphylaxis-2020-grade-document.pdf</ref> | ||
*Send home with an epinephrine autoinjector! (Epi-Pen) | **NPV of 1-hour observation was 95%, with NPV for biphasic anaphylaxis after >6 hours of observation of 97.3% <ref>Shaker M, Wallace D, Golden DBK, Oppenheimer J, Greenhawt M. Simulation of health and economic benefits of extended observation of resolved anaphylaxis. JAMA Netw Open 2019;2:e1913951.</ref> | ||
*Up to 6% of the people with anaphylaxis have a repeat ED visit for anaphylaxis within 7 days<ref name="biphasic">Grunau BE et al. Incidence of Clinically Important Biphasic Reactions in Emergency Department Patients With Allergic Reactions or Anaphylaxis. Ann Emerg Med. 2013 Nov 13</ref> | *Send home with an [[epinephrine]] autoinjector! (Epi-Pen) | ||
**Up to 6% of the people with anaphylaxis have a repeat ED visit for anaphylaxis within 7 days<ref name="biphasic">Grunau BE et al. Incidence of Clinically Important Biphasic Reactions in Emergency Department Patients With Allergic Reactions or Anaphylaxis. Ann Emerg Med. 2013 Nov 13</ref> | |||
==See Also== | ==See Also== | ||
*[[Allergic Reaction]] | *[[Allergic Reaction]] | ||
*[[Angioedema]] | *[[Angioedema]] | ||
==External Links== | |||
==References== | ==References== | ||
Latest revision as of 10:27, 11 November 2025
This page is for adult patients. For pediatric patients, see: Anaphylaxis (peds).
Background
- Type I hypersensitivity reaction that is either severe in nature or having two or more organ systems involved.
- Clinically Anaphylaxis and its treatment is virtually identical whether it is the traditional IgE dependent anaphylaxis reaction (vast majority), or the IgE independent anaphylactoid reaction
- Precipitants
- Food (most common)
- Medications
- Insect stings
- Latex
- Aerobic exercise
- Idiopathic (rare)
Clinical Features
Raised urticaria
Angioedema of tongue
- Cutaneous symptoms (90%)
- Hives
- Angioedema
- Itching
- Morbilliform rash
- Respiratory symptoms (70%)
- Wheezing
- Shortness of breath
- Throat itching or tightness
- Hoarseness
- Stridor
- Hypoxia, cyanosis
- Gastrointestinal symptoms (40%)
- Abdominal pain
- Nausea, vomiting
- Diarrhea
- Cardiovascular symptoms (35%)
- Hypotension
- Chest pain
- Palpitations
- Central Nervous System
- Uneasiness
- Altered mental status
- Headache, dizziness, confusion
- Syncope
Expected Course
Uniphasic (80-90%)
- Symptoms peak within 30 minutes to 1 hour after onset, resolve within 30 minutes to 1 hour of receiving treatment[1]
Biphasic (10-20%)
Biphasic reactions are rare and can occur anywhere from 10 minutes up to six days after an initial reaction.[2]
- Uniphasic response, followed by asymptomatic period of hour or more, then return of symptoms
- The second phase does not necessarily resemble the first!
- More likely with a severe initial presentation or repeated epinephrine doses. Additionally hypotension, widened pulse pressure, unknown trigger, and drug trigger in children[3][4]
- Little evidence to support the use of discharge steroids to prevent a biphasic reaction
- 0.4% of patients with anaphylaxis had a rebound event while in the ED[5]
Differential Diagnosis
Acute allergic reaction
- Allergic reaction/urticaria
- Anaphylaxis
- Angioedema
- Anxiety attack
- Asthma exacerbation
- Carcinoid syndrome
- Cold urticaria
- Contrast induced allergic reaction
- Scombroid
- Shock
- Transfusion reaction
Shock
- Cardiogenic
- Acute valvular Regurgitation/VSD
- CHF
- Dysrhythmia
- ACS
- Myocardial Contusion
- Myocarditis
- Drug toxicity (e.g. beta blocker, CCB, or bupropion OD)
- Obstructive
- Distributive
- Hypovolemic
- Severe dehydration
- Hemorrhagic shock (traumatic and non-traumatic)
Erythematous rash
- Positive Nikolsky’s sign
- Febrile
- Staphylococcal scalded skin syndrome (children)
- Toxic epidermal necrolysis/SJS (adults)
- Afebrile
- Febrile
- Negative Nikolsky’s sign
- Febrile
- Afebrile
Evaluation
Anaphylaxis is highly likely when ANY ONE of the following criteria is fulfilled[6][7]
Criterion 1 (90% of patients)
- Acute onset of an illness involving the skin, mucosal tissue, or both AND at least one of the following:
Criterion 2 (10-20% of patients)
- TWO OR MORE of the following that occur rapidly after exposure to a LIKELY allergen for that patient
- Involvement of the skin-mucosal tissue (hives, swollen lips-tongue-uvula)
- Respiratory compromise
- Hypotension or associated symptoms
- Persistent gastrointestinal symptoms: (vomiting, diarrhea, crampy abdominal pain)
Criterion 3
- Hypotension after exposure to a KNOWN allergy for that patient (minutes to hours):
- Adults: systolic blood pressure (SBP) <90 mmHg or >30% reduction from baseline
- Pediatrics
- 1 month - 1 year: SBP <70 mmHg
- 1 year - 10 years: SBP <(70 mmHg + [2 x age])
- 11 years - 17 years: SBP <90 mmHg
Management
- Epinephrine
- 1:1000 IM 0.3 - 0.5mg (0.3 - 0.5mL) every 5 - 15 minutes [8] [9]
- 0.5mg for adults >50kg is strongly associated with a reduction in escalation of care [10]
- Intramuscular injection of epinephrine into the thigh as the preferred route and site of injection [11] [12]
- If response to IM is inadequate: give epinephrine infusion 1:10,000 2 - 10 µg/min
- How to make a quick epinephrine drip: Take your code-cart epinephrine (it does not matter if it is 1:1,000 or 1:10,000) and inject 1mg into a liter bag of NS. Final concentration is 1mcg/ml. Run at 1cc/min and titrate to effect.
- 1:1000 IM 0.3 - 0.5mg (0.3 - 0.5mL) every 5 - 15 minutes [8] [9]
- Corticosteroids
- Methylprednisolone: 125mg IV (2mg/kg in children)
- Dexamethasone: 10mg IV or PO (0.6mg/kg in children)
- Evidence:
- Supplemental oxygen
- Consider endotracheal intubation if airway edema present
- Normal saline bolus
- If unresponsive to epinephrine assume distributive shock and give 1 - 2 liters of normal saline
- Also consider
- Albuterol for bronchospasm resistant to IM epinephrine
- Antihistamines (for symptom control AFTER hemodynamically stable)
- Diphenhydramine: 25 to 50mg IV (1mg/kg in children)
- Ranitidine: 50mg IV (0.5mg/kg in children) (has been found to improve urticaria but not angioedema at 2 hours[16])
- Cetirizine 10mg IV (6-11 years old: 5-10 mg IV; 6 mo - 5 years: 2.5 mg IV)
- AVOID promethazine as this can worsen hypotension
- Glucagon
- 1 - 5mg IV over 5 minutes followed by infusion of 5 - 15 µg/min[17]
- If taking beta-blocker AND unresponsive to epinephrine
- Consider adding additional pressor support if persistent hypotension present
- For example: vasopressin 2-8 units for persistent refractory shock (case series only)[18][19]
- Norepinephrine 0.05 to 0.5 mcg/kg per minute
Disposition
Admit
- Severe and moderate presentations, especially if symptoms did not respond promptly to epinephrine or required repeat dosing
- Labs that may be requested by allergist/admitting team if uncertain diagnosis
- Histamine level - serum elevation 30-60 min following anaphylaxis, window easily missed
- Tryptase - peaks at 2-4 hrs, remains elevated 6-12 hrs
Discharge
- Consider discharge after 1 hour observation, if no severe symptoms and no repeat epinephrine doses (AAAAI recommendations)[4]
- NPV of 1-hour observation was 95%, with NPV for biphasic anaphylaxis after >6 hours of observation of 97.3% [20]
- Send home with an epinephrine autoinjector! (Epi-Pen)
- Up to 6% of the people with anaphylaxis have a repeat ED visit for anaphylaxis within 7 days[5]
See Also
External Links
References
- ↑ Ewan PW. ABC of allergies – Anaphylaxis, BMJ 1998; 316: 1442-1445
- ↑ Milne K. Biphasic Allergic Reactions: Observation, Treatment Guidelines http://www.acepnow.com/article/biphasic-allergic-reactions-observation-treatment-guidelines/
- ↑ Ellis AK, Day JH: Incidence and characteristics of biphasic anaphylaxis: A prospective evaluation of 103 patients. Ann Allergy Asthma Immunology. 2007; 98:64-69
- ↑ 4.0 4.1 Shaker MS, Wallace DV, Golden DBK, et al. Anaphylaxis-a 2020 practice parameter update, systematic review, and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) analysis. J Allergy Clin Immunol 2020; 145:1082. https://www.aaaai.org/Aaaai/media/Media-Library-PDFs/Professional%20Education/Podcasts/Anaphylaxis-2020-grade-document.pdf
- ↑ 5.0 5.1 Grunau BE et al. Incidence of Clinically Important Biphasic Reactions in Emergency Department Patients With Allergic Reactions or Anaphylaxis. Ann Emerg Med. 2013 Nov 13
- ↑ Brown SGA, Mullins RJ and Gold MS. Anaphylaxis: diagnosis and management, MJA 2006; 185: 283–289
- ↑ Lieberman P et al. The diagnosis and management of anaphyalxis: An updated practice parameter, J Allergy Clin Immunol 2005;115;3:S483-S523
- ↑ Dhami S. et al. Management of anaphylaxis: a systematic review. Allergy. 69 (2014) 168–175. http://onlinelibrary.wiley.com/store/10.1111/all.12318/asset/all12318.pdf?v=1&t=hrspdbpk&s=8067bfd5903c7ffebf4a274f062a71633ebe0507
- ↑ Sheikh A, Shehata YA, Brown SGA, Simons FER. Adrenaline (epinephrine) for the treatment of anaphylaxis with and without shock. Cochrane Database of Systematic Reviews 2008, Issue 4. Art. No.: CD006312. DOI:10.1002/14651858.CD006312.pub2
- ↑ Retrospective comparison between 0.3 mg and 0.5 mg dosing of intramuscular epinephrine for anaphylaxis. Am J Emerg Med. 2025 Oct 10;99:270-275. doi: 10.1016/j.ajem.2025.10.020.
- ↑ Simons FER, Gu X, Simons KJ. Epinephrineabsorption in adults: Intramuscular versus subcutaneous injection, J Allergy Clin Immunol 2001;108:871-3
- ↑ Epinephrine absorption in adults: Intramuscular versus subcutaneous injection. Simons, F.Estelle R. et al. Journal of Allergy and Clinical Immunology, Volume 108, Issue 5, 871 - 873
- ↑ Liyanage CK, et al. Corticosteroids in management of anaphylaxis; a systematic review of evidence. Eur Ann AllErgy Clin immunol. 2017. 49(5): 196-207. 10.23822/EurAnnACI.1764-1489.15.
- ↑ Liyanage CK, et al. Corticosteroids in management of anaphylaxis; a systematic review of evidence. Eur Ann AllErgy Clin immunol. 2017. 49(5): 196-207. 10.23822/EurAnnACI.1764-1489.15.
- ↑ Liyanage CK, et al. Corticosteroids in management of anaphylaxis; a systematic review of evidence. Eur Ann AllErgy Clin immunol. 2017. 49(5): 196-207. 10.23822/EurAnnACI.1764-1489.15.
- ↑ Lin, RY et al. Improved Outcomes in Patients With Acute Allergic Syndromes Who Are Treated With Combined H1 and H2 Antagonists. Annals of Emergency Medicine. 36:5 NOVEMBER 2000.
- ↑ Campbell RL, et al. Emergency department diagnosis and treatment of anaphylaxis: a practice parameter. Ann Allergy Asthma Immunol. 2014; 113:599e608.
- ↑ Schummer et al. The Pivotal Role of Vasopressin in Refractory Anaphylactic Shock. Anesthesia & Analgesia: August 2008 - Volume 107 - Issue 2 - pp 620-624.
- ↑ Dünser et al. Treatment of Anaphylactic Shock: Where Is the Evidence? Anesthesia & Analgesia: August 2008 - Volume 107 - Issue 2 - pp 359-361
- ↑ Shaker M, Wallace D, Golden DBK, Oppenheimer J, Greenhawt M. Simulation of health and economic benefits of extended observation of resolved anaphylaxis. JAMA Netw Open 2019;2:e1913951.
