Anaphylactically Shocking!

From 2011 to 2016, the number of people admitted to hospital suffering from an allergic reaction increased by a third in the UK. This sharp influx of admittances is due to a phenomenon described in the "Hygiene Hypothesis" which states that due to a lack of early exposure in one's childhood to pathogens and microbes in the surrounding environment, their body's immune system has not properly developed and is subsequently more susceptible to allergic diseases later on in life. An interesting statistic is that there are a lower percentage of people with allergies in less developed countries than in more developed countries. This is a result of living in conditions less hygienic than our own exposing their population to viruses, parasites and microbes from an early age, facilitating the growth of their immune system. In an irony of fate, our cleanliness has led to our increased vulnerability to common (and in most cases harmless) substances.

An allergic reaction is defined as an overreaction (or hypersensitive reaction) of the body to a harmless substance by recognising it as an invading pathogen and invoking the immune system to deal with it. Hay fever is the most well-known of the allergic conditions; pollen, produced from plants and trees, gets into your system and the body registers it as a dangerous pathogen. As a result, the body produces the antibody immunoglobulin E, in the area where the pathogen was detected, which binds to receptors on mast cells, causing them to release histamines. Histamines are the operative chemical in allergic reactions and are what cause most of the symptoms to occur. Histamines increase blood flow to the target region, causing inflammation and the skin to turn red. If the allergen is in the nose, then mucus will be produced, if the allergen is in the eyes then they will tear up and begin to itch. Symptoms are very region-specific.

Allergic reactions can vary in symptoms, some include:
- Wheezing, chest tightness.
- Itchy, red and watery eyes.
- Swollen lips, tongue or face.
- Dry, red and cracked skin.
In some extreme cases, anaphylaxis may occur. Anaphylaxis is when a person is subject to a sudden onslaught of allergic symptoms that result in anaphylactic shock. Anaphylactic shock can be fatal as it is a state of being when blood pressure in the body is dangerously low and the organs aren't getting enough blood, threatening to shut them down. If anaphylaxis is not treated quickly, then the body begins shutting down and will swiftly lead to death.

Doctors treat allergic reactions in largely the same way, with antihistamines. However, the level of severity dictates the level of antihistamines given. Someone suffering from anaphylactic shock requires a large dose of antihistamines very quickly in order to counteract their effect. Someone suffering from hay fever on the other hand requires long-lasting antihistamines but in a much reduced quantity to deal with irritative symptoms. People with hay fever are prescribed drugs such as cetirizine (Zyrtec) and Loratadine (Claritin), but as with every drug of course, there are side-effects. These include drowsiness, nausea, dizziness and sometimes a whole plethora of unpleasantness. However, with the large improvement they give to the quality of life in other areas, these are bearable.

Thank you very much for reading, I hope this helped shed some light on allergic reactions and their mechanisms of action. This has been Timothy K. Bosse, hoping you have a great allergy free day!

Citations:
https://www.emedicinehealth.com/allergic_reaction/article_em.htm
https://www.aaaai.org/conditions-and-treatments/conditions.../immunoglobulin-e-(ige)
https://www.amnh.org/learn/biodiversity_counts/ident_help/.../parts_of_flower.htm
https://www.nhs.uk/conditions/allergies/symptoms/

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