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Show full transcript for Allergic Reactions and Anaphylaxis video

An allergy is an adverse reaction that the body has to a particular food or substance in the environment. Most substances that cause allergies are not harmful and have no effect on people who are not allergic to them, and any substance that triggers an allergic reaction is called an allergen. Common allergens include pollen, latex, nuts, eggs and pets. An allergy develops when the body's immune system reacts to an allergen as though it was an infection-like threat. It produces antibodies to fight off the allergen in a reaction called an immune response. Next time the person comes into contact with the allergen, the body remembers the previous exposure and therefore produces more antibodies. This causes a release of chemicals in the body that lead to an allergic reaction.

Common allergic disorders include asthma, eczema and hay fever. Symptoms of an allergy can include sneezing, wheezing, coughing and skin rashes. The nature of the symptom depends on how you came into contact with the allergen. For example, you may experience problems with your airways if you breathe in pollen. Anaphylactic reactions are those that cause a serious reaction that affects the respiratory system and this can be life-threatening. The allergen could be by ingesting, inhaling, absorbing through the skin or from an injection like a bee sting. Allergic reactions are not just anaphylactic types of reaction, they can be different levels of reactions which include allergies, sensitivity and intolerance.

Sensitivity is an exaggeration of a normal side effect produced by contact with the substance. For example, the caffeine in a cup of coffee may cause extreme symptoms such as palpitations and trembling when it would normally only have that effect if taken in very large quantities.

Intolerance is where a substance like lactose or gluten causes unpleasant symptoms such as diarrhoea for a variety of reasons but does not involve the immune system. People with an intolerance to certain foods can typically eat a small amount without having any problems but others will have extreme pain, sickness, diarrhoea and it may take a few days to get over the exposure.

People with a food allergy will have a bad reaction even if they come into contact with a tiny amount of something for which they are allergic to. Where someone has an intolerance or sensitivity, treatment is often to remove the source and let nature take its course, but where there's as an anaphylactic reaction to an allergen, auto-injectors are often used to inject a pre-set dose of adrenaline into the muscle of the body, which reduces the effects until emergency help arrives.

Signs and symptoms of an anaphylactic reaction include itchy skin or a raised red rash, swollen eyes, lips, hands or feet; feeling lightheaded or faint; narrowing of the airways which can cause wheezing and breathing difficulties; abdominal pain; nausea and vomiting, and also eventually collapsing and unconsciousness. Anaphylaxis should always be treated as a medical emergency. If you suspect that you or someone else is experiencing symptoms of anaphylaxis, you should immediately dial 999 for an ambulance.

There are different types of auto-injector. These auto-injectors are prescribed by a doctor, they are not something you can just buy at the chemist, so each individual person would have their own prescription. It may well be that this person has more than one auto-injector because if the first auto-injector hasn't worked after 5 to 15 minutes, they can administer a second dose. All units are single-dose syringes. If a second dose is administered, the emergency services must be told so they know exactly how much adrenaline has been administered. There are three key ones on the market at the present time but this can of course change.

The first one we're going to look at is the EpiPen. The EpiPen comes in two types, the standard EpiPen and the EpiPen Junior. As with all of the auto-injectors, the instructions are clearly printed on the unit. The blue cap shows you the top of the EpiPen, this is the safety cap which makes sure that the needle does not come out when not in use. Then remove the safety cap and firmly push the auto-injector into the thigh. This can be done through clothing, but make sure that the needle will not go through any thick seams in the clothes or anything in pockets. Once the needle has hit, hold it in place for 3 seconds and then remove it. With the EpiPen, you do not need to rub the area after, as the adrenaline will diffuse itself.

The next one of the injectors we are going to look at is the Emerade, which has a longer needle than other auto-injectors. The Emerade is designed to be injected into body muscle rather than body fat. 

You remove the cap and press it firmly into your thigh and hold it there for five seconds. Then remove it and rub the area to allow the adrenaline to diffuse around the area quickly. As stated before, the person may have two of these and they may need to have another dose if that proves necessary.

The final one we're going to look at is the Jext.  The Jext is a similar unit to the EpiPen, but again, there are some key differences. There are two windows on the unit. The first one will either be red or green. Red means it is ready to be used, and green means it has already been used. The other window actually lets you see the drug itself. The drug should be clear and colourless. If it is not, then you should not use the unit and get it replaced as soon as possible. Remove the yellow cap and place the black end against your thigh. Push it inwards and slowly count to 10. Then gently pull upwards and the needle will automatically become covered. Rub the area for at least 10 seconds to help the drug to diffuse quickly through your system.

Once the adrenaline has been administered, either by you or the patient themselves, leave them where they are – don’t let them stand up until the Emergency Services arrive. Even if the person is showing signs of recovery, always dial 999 with anybody who has an anaphylactic emergency. Also, make sure you hand over the used auto-injectors to the emergency services, as not only will they be able to dispose of the auto-injectors safely, but more importantly, they will then know exactly what has been administered.