Anp

Anaphylaxis
Synonyms	N/A
Pronounce	N/A
Specialty	N/A
Symptoms	Hives, swelling, shortness of breath, vomiting, lightheadedness
Complications	Anaphylactic shock, cardiac arrest
Onset	Rapid
Duration	Variable
Types	N/A
Causes	Allergic reaction
Risks	Asthma, eczema, allergic rhinitis
Diagnosis	Based on symptoms and history
Differential diagnosis	N/A
Prevention	N/A
Treatment	Epinephrine, antihistamines, corticosteroids
Medication	N/A
Prognosis	N/A
Frequency	0.05–2% of people
Deaths	N/A

Anaphylaxis is a severe, potentially life-threatening allergic reaction that can occur rapidly. It is characterized by a range of symptoms that can affect multiple body systems, including the skin, respiratory system, gastrointestinal tract, and cardiovascular system.

Pathophysiology

Anaphylaxis is a type I hypersensitivity reaction mediated by immunoglobulin E (IgE). Upon exposure to an allergen, IgE antibodies trigger the release of histamine and other inflammatory mediators from mast cells and basophils. This leads to widespread vasodilation, increased vascular permeability, and smooth muscle contraction.

Causes

Anaphylaxis can be triggered by a variety of allergens, including:

• Foods: Peanuts, tree nuts, shellfish, milk, eggs, and wheat are common triggers.
• Medications: Antibiotics such as penicillin, nonsteroidal anti-inflammatory drugs (NSAIDs), and anesthetics.
• Insect stings: Bee, wasp, and ant stings.
• Latex: Exposure to latex products.
• Exercise: Exercise-induced anaphylaxis can occur, sometimes in conjunction with food intake.

Symptoms

Symptoms of anaphylaxis can vary but often include:

• Cutaneous: Urticaria (hives), angioedema (swelling), flushing.
• Respiratory: Dyspnea (shortness of breath), wheezing, stridor, cough.
• Gastrointestinal: Nausea, vomiting, diarrhea, abdominal pain.
• Cardiovascular: Hypotension, tachycardia, syncope.
• Neurological: Dizziness, confusion, loss of consciousness.

Diagnosis

Diagnosis of anaphylaxis is primarily clinical, based on the rapid onset of symptoms following exposure to a known or potential allergen. Key diagnostic criteria include:

• Acute onset of skin or mucosal symptoms with respiratory compromise or reduced blood pressure.
• Two or more of the following after exposure to a likely allergen: skin/mucosal symptoms, respiratory compromise, reduced blood pressure, or persistent gastrointestinal symptoms.
• Reduced blood pressure after exposure to a known allergen.

Treatment

The primary treatment for anaphylaxis is the prompt administration of epinephrine. Additional treatments may include:

• Antihistamines: To alleviate skin and mucosal symptoms.
• Corticosteroids: To prevent biphasic reactions.
• Oxygen therapy: For patients with respiratory distress.
• Intravenous fluids: To treat hypotension.

Prevention

Preventive measures include:

• Avoidance of known allergens.
• Carrying an epinephrine auto-injector for individuals at risk.
• Wearing medical alert identification.
• Education on recognizing early symptoms and proper use of epinephrine.

Prognosis

With prompt treatment, the prognosis for anaphylaxis is generally good. However, delayed treatment can lead to severe complications, including anaphylactic shock and death.

Epidemiology

Anaphylaxis affects approximately 0.05–2% of the population, with increasing incidence rates. It is more common in individuals with a history of atopy, such as asthma, eczema, or allergic rhinitis.

See also

• Allergy
• Hypersensitivity
• Mast cell