Anaphylaxis is a severe, potentially life-threatening allergic reaction that can occur rapidly and affects multiple body systems. It is a medical emergency that requires immediate treatment. This article explores the symptoms, causes, risk factors, diagnosis, treatment, and prevention of anaphylaxis.

Symptoms of Anaphylaxis

Anaphylaxis symptoms can vary but typically appear within minutes to a few hours after exposure to an allergen. Common symptoms include:

• Skin Reactions: Hives, itching, and flushed or pale skin.

• Swelling: Particularly of the face, lips, tongue, and throat, which can cause difficulty breathing.

• Respiratory Symptoms: Wheezing, shortness of breath, and a tight feeling in the chest.

• Cardiovascular Symptoms: Rapid or weak pulse, low blood pressure, and dizziness or fainting.

• Gastrointestinal Symptoms: Nausea, vomiting, diarrhea, and abdominal pain.

• Neurological Symptoms: Anxiety, confusion, and a sense of impending doom.
  

Causes of Anaphylaxis

Anaphylaxis is triggered by the immune system overreacting to an allergen. Common triggers include:

• Food Allergies: Peanuts, tree nuts, shellfish, fish, milk, eggs, soy, and wheat are common food allergens.

• Medications: Antibiotics (such as penicillin), aspirin, and other NSAIDs, and certain chemotherapy drugs.

• Insect Stings: Bees, wasps, hornets, and fire ants.

• Latex: Products made from natural rubber latex.

• Exercise: Exercise-induced anaphylaxis can occur, sometimes related to food intake before exercise.

• Unknown: In some cases, the cause of anaphylaxis is never identified (idiopathic anaphylaxis).

Risk Factors

Certain factors increase the risk of anaphylaxis:

• Previous Anaphylaxis: Having had an anaphylactic reaction before increases the risk of future reactions.

• Allergies or Asthma: People with asthma or multiple allergies are at higher risk.

• Family History: A family history of anaphylaxis or other allergic reactions can increase risk.

• Certain Conditions: Conditions like mastocytosis, which involves an excess of mast cells, can raise the risk.

  
  

Diagnosis

Diagnosis of anaphylaxis is primarily clinical, based on the rapid onset of symptoms following exposure to a known allergen. Steps in diagnosis include:

• Medical History: Documentation of previous allergic reactions and known allergens.

• Physical Examination: Assessment of symptoms, including respiratory and cardiovascular status.

• Laboratory Tests: Measurement of tryptase levels in the blood, which can be elevated after an anaphylactic reaction.

• Allergy Testing: Skin tests or blood tests to identify specific allergens responsible for the reaction.

  
  

Treatment

Immediate treatment is crucial for anaphylaxis:

• Epinephrine Injection: The first-line treatment, usually administered via an auto-injector (such as an EpiPen).

• Call for Emergency Help: Contact emergency medical services immediately.

• Additional Medications: After epinephrine, antihistamines and corticosteroids may be given to manage symptoms.

• Oxygen Therapy: For patients experiencing severe respiratory distress.

• Intravenous Fluids: To treat low blood pressure and shock.

• Observation: Patients should be monitored in a medical facility for several hours after an episode, as biphasic anaphylaxis can occur.

Prevention

Preventing anaphylaxis involves avoiding known allergens and being prepared for emergencies:

• Avoidance: Strictly avoid known allergens. Read food labels, inform healthcare providers of allergies, and be cautious in environments where allergens may be present.

• Epinephrine Auto-Injectors: Carry an auto-injector at all times if you have a history of anaphylaxis. Ensure that friends, family, and colleagues know how to use it.

• Allergy Management Plan: Work with an allergist to develop a personalized plan for managing allergies and preventing anaphylaxis.

• Medical Identification: Wear a medical alert bracelet that identifies your allergies.

Editorial History

Written By:

Nikita Kewalramani

Reviewed By:

Dr. Sachin Kadoo

MBBS, MD.

Last updated: Aug 3, 2024

References:

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