What causes an anaphylactic reaction?
In most allergic reactions the resulting chemicals are released locally into the tissues in a particular part of the body (skin, eyes etc.). This means the symptoms of the allergic reaction usually only occur in this area.
In anaphylaxis, the chemicals that cause the allergic symptoms (e.g. histamine) are released into the bloodstream. The symptoms of anaphylaxis usually occur within minutes of exposure to the trigger substance (allergen) but sometimes an hour or so later.
The most common causes of anaphylactic reactions include:
- Foods – including nuts, milk, fish, shellfish, eggs and some fruits
- Medicines and drugs – including some antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) like aspirin
- Insect stings – particularly wasp and bee stings
- General anaesthetic
- Contrast agents – dyes used in some medical tests to help certain areas of your body show up better on scans
- Latex – a type of rubber found in some rubber gloves and condoms.
In some cases, there’s no obvious trigger. This is known as idiopathic anaphylaxis.
Symptoms of anaphylaxis
Any or all of the following symptoms may be present during an anaphylaxis reaction:
- Swelling of tongue and/or throat
- Difficulty in swallowing or speaking
- Vocal changes (hoarse voice)
- Wheeze or persistent cough or severe asthma
- Difficult or noisy breathing
- Stomach cramps or vomiting after an insect sting
- Dizziness / collapse / loss of consciousness (due to a drop in blood pressure) ( floppiness in babies).