Causes and Risk Factors of Anaphylaxis
Anaphylaxis occurs when the immune system overreacts to a substance, mistakenly identifying it as harmful and releasing a flood of chemicals such as histamine. These chemicals cause blood vessels to widen, airway tissues to swell, and blood pressure to drop dangerously. Read more about the causes and risk factors of anaphylaxis below.
Common Causes (Triggers)
- Insect Stings
- Bee or wasp stings can trigger a severe reaction, particularly in sensitised individuals
- Food Allergies
- Peanuts, shellfish, eggs, milk, tree nuts, and wheat
- Food is the leading cause of anaphylaxis in children
- Medication Allergies
- Antibiotics like penicillin or sulfa drugs
- NSAIDs (e.g. ibuprofen), anaesthetics, and some vaccines
- Latex
- Used in medical gloves, balloons, and some contraceptives
- Exercise
- Can trigger anaphylaxis on its own or when combined with certain foods
- Idiopathic
- In some cases, the trigger is unknown
Risk Factors
- Previous anaphylaxis – increases the risk of future severe reactions
- Allergic conditions – such as asthma, eczema, or hay fever
- Family history of anaphylaxis or severe allergies
- Age – children may be more sensitive to food allergens; adults to medications
- Mast cell disorders – rare conditions that predispose to sudden allergic responses
In South Africa, bee stings and food-related anaphylaxis are among the most common causes. Limited access to adrenaline auto-injectors (e.g. EpiPens) in public healthcare remains a concern.
Let’s now look at how anaphylaxis is diagnosed — especially when the reaction happens rapidly.
👉 [Next: Diagnosis of Anaphylaxis]
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