What is it?
Anaphylaxis (also known as ‘anaphylactic shock’ or ‘anaphylaxia’) is a severe allergic reaction that affects the patient’s airways, heart, circulation, gut, and skin. The reaction usually occurs within minutes of exposure to the triggering allergen but can begin up to 2 or even 3 hours after initial contact. This reaction is potentially life-threatening and should be treated immediately by a medical professional.
Signs and Symptoms of Anaphylaxis
As anaphylaxis
affects various systems within the body, there are many signs and symptoms of
the reaction.
- Trouble swallowing
- Wheezing and a tight test
- Nausea, abdominal pain, and vomiting
- Diarrhoea
- Feeling weak and floppy
- Swelling of the lips, throat or anywhere on the body
- Collapsing and/or passing out
- Flushed skin (this may be widespread)
- Sudden drop in blood pressure
- Itchy rash (or hives)
Causes of Anaphylaxis
Anaphylaxis is
almost exclusively caused by an allergy, with the vast majority of cases being
triggered by one of the 14 major allergens;
- celery
- cereals containing gluten – including wheat, rye, barley and oats
- crustaceans – such as prawns, crabs and lobsters
- eggs
- fish
- lupin
- milk
- molluscs – such as mussels and oysters
- mustard
- tree nuts – including almonds, hazelnuts, walnuts, brazil nuts, cashews, pecans, pistachios and macadamia nuts
- peanuts
- sesame seeds
- soybeans
- sulphur dioxide and sulphites (if they are at a concentration of more than ten parts per million)
Having an allergy to any of these major allergens increases the risk of anaphylaxis. The incidence of anaphylaxis appears to be increasing in the UK. Between 1992 and 2012, the number of yearly hospital admissions tracked by the NHS increased by over 600%, from approximately 1,150 admissions to over 8,200 [1]. The trend seems to be continuing, with admission for under 18’s Between 2014 and 2019 has risen by a staggering 70% [2].
Treatment and Outlook
If you are
experiencing a bout of anaphylaxis, it is important to act fast. The first
course of action is to administer adrenaline. Pre-loaded auto-injectors
containing adrenaline are prescribed to individuals at high risk of
anaphylaxis. These auto-injectors should be available at all times – no
exceptions.
Adrenaline is
crucial in these first few minutes as it acts to rapidly open up the patient’s
airways, get their blood pressure back up and stop any swelling. If you suspect
that you’re experiencing anaphylaxis but aren’t certain, it is recommended that
adrenaline is administered anyway – as it’s better to be safe than sorry.
Following
administering adrenaline, an ambulance should be called immediately, even if
the person’s condition improves upon injecting adrenaline. If their condition
gets worse after making that initial 999 call, call them again to ensure an
ambulance is dispatched, as you will be put on a higher priority. 5-10 minutes
after the first adrenaline injection, a second shot should be administered if
the symptoms of anaphylaxis remain.
Remember, anaphylaxis always requires an immediate emergency response. In the US, an estimated in the US, an estimated, 1% of hospitalisations due to anaphylaxis have a fatal outcome [3], so medical attention is vital.
Risk Factors
There are several
risk factors associated with anaphylaxis that can be partly controlled or seen
as times, to take extra precautionary measures. These include;
- Poorly controlled asthma
- Current or recent infection
- Exercise prior to or shortly after contact with the allergen
- Suffering from hay fever or other aeroallergen symptoms
- Emotional stress
- Drinking alcohol
Research has also
highlighted a few other risk factors to be aware of. For example, this study
found that as a patient’s age increases, their risk of developing severe
cardiovascular symptoms increases substantially [4].
Suffering from a
pre-existing respiratory illness can also be a factor, as studies have shown
that poor management of allergic bronchial asthma drastically increases the
risk of severe anaphylaxis [5].
Lastly, it appears that male patients are more likely to develop anaphylaxis from insect venom compared to females [6]. This has been observed in both male adults and children.
Prevention
The best way to
prevent anaphylaxis is to be aware of your allergies and be mindful to avoid
them wherever possible. Many people are unaware of any allergies they may have,
and most health professionals don’t carry out routine testing without prior
evidence of an existing allergy or a family history.
Some people may feel that this is something they want to take into their own hands and opt for allergy testing to ensure they don’t remain ignorant of any potential allergies they may have.
Final Thoughts
While the number of yearly deaths from anaphylaxis is relatively small, it still concerns us to know we may be at risk of anaphylaxis. And it’s far from an enjoyable experience either way. This life-threatening condition can be avoided with diligence and the knowledge of what your body may react adversely to.
Research
[1] Turner, P.J., Gowland, M.H., Sharma, V., Ierodiakonou, D., Harper, N., Garcez, T., Pumphrey, R. and Boyle, R.J. (2015). Increase in anaphylaxis-related hospitalizations but no increase in fatalities: An analysis of United Kingdom national anaphylaxis data, 1992-2012. Journal of Allergy and Clinical Immunology, 135(4), pp.956-963.e1. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4382330/ [Accessed 2 Mar. 2020].
[2] NHS Digital. (2018). Hospital admissions for allergies and anaphylactic shock – NHS Digital. [online] Available at: https://digital.nhs.uk/data-and-information/find-data-and-publications/supplementary-information/2018-supplementary-information-files/hospital-admissions-for-allergies-and-anaphylactic-shock [Accessed 2 Mar. 2020].
[3] Ma, L., Danoff, T.M. and Borish, L. (2014). Case fatality and population mortality associated with anaphylaxis in the United States. Journal of Allergy and Clinical Immunology, [online] 133(4), pp.1075–1083. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0091674913016424 [Accessed 2 Mar. 2020].
[4] Worm, M., Babina, M. and Hompes, S. (2013). Causes and risk factors for anaphylaxis. Journal der Deutschen Dermatologischen Gesellschaft = Journal of the German Society of Dermatology : JDDG, [online] 11(1), pp.44–50. Available at: https://www.ncbi.nlm.nih.gov/pubmed/23181736 [Accessed 2 Mar. 2020].
[5] Iribarren, C., Tolstykh, I.V., Miller, M.K. and Eisner, M.D. (2010). Asthma and the prospective risk of anaphylactic shock and other allergy diagnoses in a large integrated health care delivery system. Annals of allergy, asthma & immunology : official publication of the American College of Allergy, Asthma, & Immunology, [online] 104(5), pp.371–7. Available at: https://www.ncbi.nlm.nih.gov/pubmed/20486326?dopt=Abstract [Accessed 2 Mar. 2020].
[6] Ruëff, F., et al. (2009). Predictors of severe systemic anaphylactic reactions in patients with Hymenoptera venom allergy: importance of baseline serum tryptase-a study of the European Academy of Allergology and Clinical Immunology Interest Group on Insect Venom Hypersensitivity. The Journal of allergy and clinical immunology, [online] 124(5), pp.1047–54. Available at: https://www.ncbi.nlm.nih.gov/pubmed/19895993?dopt=Abstract [Accessed 2 Mar. 2020].
