Anaphylaxis is an extreme and very severe allergic reaction. The person whole body is being affected. Normally within minutes of exposure to the substance which arise the allergic reaction (allergen). However, there are cases were the reaction can take some hours before the person react.
Common causes for anaphylaxis
reaction can be foods such as peanuts, tree nuts (e.g. almonds, walnuts, cashews, and Brazil nuts), sesame, fish, shellfish, dairy products, eggs and gluten.
Other substances include wasp or bee stings, penicillin, other drug, injection or even rubber (natural latex) which is a potential problem with condom usage.
The symptoms are varied:
• flushing of the skin
• swelling of throat and mouth
• alterations in heart rate
• difficulty in swallowing or speaking
• severe asthma
• abdominal pain, nausea and vomiting
• sense of impending doom
• collapse and unconsciousness
• sudden feeling of weakness (drop in blood pressure)
• nettle rash (hives) anywhere on the body
A patient may not necessarily experience all of these symptoms in the same time although, a person can react in different ways:
which comes quickly and symptoms get rapidly worse. However, once treated these symptoms go away.
a reaction that may be mild or severe to start with and followed by a length of time when there are no symptoms. Eventually these will reoccur and some symptoms will lead to breathing and blood-pressure problems.
If a patient suffers anaphylactic reaction, they will need an observation period in hospital once they have recovered in case they develop an biphasic reaction. Most biphasic reactions starts within hours of the initial reaction but occasionally are delayed. On a very rare occasions, a biphasic reaction has been known to occur after 72 hours from the initial reaction. The length of the observation period is necessary for the doctor to decide on a course of action.
The National Institute for Health and Care Excellence (NICE)
recommends that patients who have had a severe allergic reaction should be monitored for 6 – 12 hours within a hospital due to risk of a bi-phasic reaction. Children are likely to be admitted to hospital at least overnight (NICE 2011).
Protracted anaphylaxis can last for several days and may need treatment in hospital for some time.
Any allergic reaction, including the most extreme form, anaphylactic shock, occurs because the body’s immune system reacts inappropriately in response to the presence of a substance that it wrongly perceives as a threat. The symptoms are caused by the sudden release of chemical substances, including histamine, from cells in the blood and tissues where they are stored. The release is triggered by the interaction between an allergic antibody called Immunoglobulin E (IgE).
and the substance (allergen) causing the anaphylactic reaction. This mechanism is so sensitive that minute quantities of the allergen can cause a reaction. The released chemicals act on blood vessels to cause swelling. In people with asthma, the effect is mainly on the lungs. There may also be a fall in blood pressure.
are prescribed for those who are at risk. Adrenaline (also known as epinephrine) acts quickly to constrict blood vessels, relax smooth muscles in the lungs to improve breathing, stimulate the heartbeat and help to stop swelling around the face and lips.
Once a patient had an allergic reaction in the past, whatever the cause, it is likely that future reaction will be severe. Should a significant reaction to a tiny dose occurs, or skin contact, it might also be a sign that a larger dose may trigger a severe reaction. It is particularly important that those with asthma as well as allergies are seen by an allergy specialist because asthma can put a patient in a higher risk category. Anyone who believes they suffer from an allergy should see their GP. Where there is a chance of an allergy being severe, the GP should refer the patient to an NHS allergy clinic.
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