Anaphylaxis: Triggers and symptoms

Anaphylaxis is a severe allergic reaction that can be potentially life-threatening, particularly in children and adolescents (Sampson et al, 2005; Sampson et al, 2006; Hompes et al, 2011; Simons et al, 2011; Grabenhenrich et al, 2016). It can present in virtually any setting and is very unpredictable (Sheikh et al, 2008; Dinakar, 2012; Grabenhenrich et al, 2016). In fact, the more rapidly anaphylaxis develops in a patient, the more likely the reaction is to be severe and life-threatening (Lieberman et al, 2010). It has also been reported that 60% of individuals who had anaphylaxis were not equipped with the correct medication needed to treat it (Wood et al, 2014). There is therefore a need to have a deeper understanding of anaphylaxis and how to correctly assess and diagnose it (Dinakar, 2012; Grabenhenrich et al, 2016). This article, the first of a two-part series, explores common anaphylaxis triggers and looks at some of the literature on the importance of early assessment and appropriate diagnosis in children and young people.

This is becoming more important as the incidence of anaphylaxis, particularly food-induced anaphylaxis, has been increasing worldwide (Koplin et al, 2011). In the United States, not only have the numbers been increasing but also the risk of a worse outcome in teenagers and in those with a comorbidity such as asthma (Dinakar, 2012). The prevalence of anaphylaxis also appears to have been rising among the younger age groups (Shen et al, 2009; Gibbison et al, 2012). In Hochstadter et al's (2016) retrospective study in Canada the percentage of anaphylaxis cases among all emergency department had more than doubled over a 4-year period. Rates of anaphylaxis in children and young people also appear to be rising in the UK (Tse and Rylance, 2009; Gibbison et al, 2012; The Resuscitation Council UK, 2017). While Bohlke et al (2004), however, suggested that the number of cases of anaphylaxis among children and adolescents had not increased, they had examined figures from 1991 to 1997.

The rise in cases of anaphylaxis and food allergies is thought by some to be due to vitamin D deficiency (Taback and Simons, 2007; Mullins and Camargo, 2012). While the numbers of food allergies and anaphylaxis have increased and vitamin D levels in the population have been found to have decreased (Ginde et al, 2009; Osborne et al, 2011), Koplin et al (2011) suggested that further studies are required to confirm a link.

Triggers

In a large European study, Grabenhenrich et al (2016) showed that food was a frequent trigger or cause in cases of anaphylaxis (66%). Certainly, Järvinen et al (2008) found that food-related allergies were the most common cause of anaphylaxis outside the hospital environment. Foods are also the most significant triggers for IgE-mediated anaphylaxis in children (Silva et al, 2012).

In Järvinen et al's (2008) study, peanut, tree nuts, and cow's milk were responsible for >75% of reactions that required medical intervention. Grabenhenrich et al, 2016 found that cow's milk and hen's egg were prevalent causes of allergic reactions in the first 2 years of life with hazelnut and cashew allergies occurring more in preschool-aged children. It is worth noting that peanut allergies occurred in all ages (Grabenhenrich et al, 2016). This continuous changed from food allergies to insect venom—and drug-induced anaphylaxis up to the age of 10 years when things stabilised (Grabenhenrich et al, 2016). Grabenhenrich et al (2016) showed that the second main cause was insect venom such as wasp stings in 19% of cases of anaphylaxis. Hompes et al (2011) suggests that food allergens account for 58% of allergic reactions, followed by insect venom (24%) and drugs (8%). They also suggested that the most frequent food allergens were peanuts followed by tree nuts such as hazelnuts and animal-related food products (Hompes et al, 2011).

‘[Anaphylaxis] can present in virtually any setting and is very unpredictable … It has also been reported that 60% of individuals who had anaphylaxis were not equipped with the correct medication needed to treat it.’

Presentation and diagnosis

While there is clear information about the triggers of anaphylaxis, there is a lack of any consistent pattern of clinical manifestations and there is a range of possible presentations which lead to difficulty in cause diagnostics (Campbell et al, 2012; The Resuscitation Council UK, 2017). This means that patients may have been given the wrong information about their diagnosis or injections of adrenaline inappropriately (The Resuscitation Council UK, 2017). The history of exposure to a known allergen for the patient is important and anaphylaxis is therefore deemed likely when all of the following three criteria are met:

• Sudden onset and rapid deterioration of condition
• Life-threatening airway and/or breathing and/or circulation problems
• Additional signs such as flushing, urticaria, angioedema (The Resuscitation Council UK, 2017).

Identifying the signs and symptoms of anaphylaxis is essential so that nurses can initiate rapid treatment and also offer patients and their carers' advice to reduce the risk of further episodes (Bryant, 2007). Diagnosis should be based predominantly on clinical signs and symptoms where possible, but can also be confirmed through biochemical tests, such as tryptase levels (Bethel, 2013). Da Broi and Moreschi (2011), however, suggest that there is a lack of reliable laboratory biomarkers to diagnose an anaphylactic event. The signs and symptoms of anaphylaxis can be challenging to differentiate, particularly in school-aged children (Schoessler and White, 2013). School nurses need to recognise the distinctive and unique ways in which children describe and manifest anaphylactic symptoms (Schoessler and White, 2013).

It is also important to differentiate between IgE-mediated and non-IgE-mediated reactions associated with food allergy as they do not always lead to anaphylaxis. IgE-mediated reactions are triggered by the immunoglobulin E (IgE) antibody and lead to an acute, rapid onset reaction. Non-IgE-mediated reactions are usually characterised by delayed and non-acute reactions (National Institute for Health and Clinical Excellence [NICE], 2011). There can, however, be an anaphylactoid reaction which is a non-IgE mediated reaction with the same clinical picture as anaphylaxis (Uram, 2000). Certainly when both IgE-mediated and non-IgE-mediated mechanisms were a possible cause, the term anaphylactic was used to describe the reaction (Uram, 2000; NICE, 2011). Any suspected anaphylactic reaction, acute clinical features of the suspected anaphylactic reaction involving the airway and/or breathing, and/or circulation and, in most cases, associated skin and mucosal changes should be documented (NICE, 2011). It is recommended that incident should be investigated immediately to help to identify the possible trigger (NICE, 2011).

The management of anaphylaxis involves rapid diagnosis, assessment, and early initiation of drug therapy (Liberman and Teach, 2008; Lieberman et al, 2010; NICE, 2011; Simons et al, 2011). Adrenaline is the initial therapy for anaphylaxis but additional interventions such as oxygen therapy, fluid resuscitation, β-agonists, antihistamines, and corticosteroids can also be given (Liberman and Teach, 2008; Simons et al, 2011). Hompes et al (2011) showed that antihistamines (87%) and corticosteroids (85%) were often used but that there was an under-usage of adrenaline. They suggested a need for more educational measures for patients and medical staff (Hompes et al, 2011). Järvinen et al (2008) found in their study of children and adolescents with multiple food allergies that 19% of food-induced anaphylactic reactions were treated with more than one dose of adrenaline. They recommended that it is necessary to identify risk factors for severe anaphylaxis and to establish guidelines for prescribing more than one adrenaline auto-injector for children with food allergy (Järvinen et al, 2008).

After a first incident of anaphylaxis patients should be referred to an age-appropriate specialist allergy service to ‘accurately investigate, diagnose, monitor and provide ongoing management of, and patient education about, suspected anaphylaxis’ (NICE, 2011). Certainly, previous studies have highlighted the importance of attendance at a multidisciplinary allergy clinic as it was effective in improving parents' knowledge of food allergy and in reducing subsequent reactions (Dhami et al, 2014; Kapoor et al, 2004). On discharge from any health-care setting, patients and their guardians should be equipped with adrenaline auto-injectors and a written personalised action plan, which includes the signs and symptoms of anaphylaxis (Simone et al, 2011).

Young people and children with suspected anaphylaxis should have the opportunity to make informed decisions about their care and treatment, in partnership with guardians and their health professionals (NICE, 2011). Health professionals should also follow the Department of Health and Social Care's advice on consent and the code of practice that accompanies the Mental Capacity Act if patients do not have the capacity to make decisions (NICE, 2011).

Nurses therefore need to keep up to date to support educational interventions for patients. Health professionals have, however, been shown to have a lack of knowledge on the pharmacodynamics of adrenaline and the ideal dosage in children (Kastner et al, 2010). Drupad et al (2015) carried out a study in India, which also showed that there was a lack of knowledge about anaphylaxis and its management among health providers in an emergency care setting. Ibrahim et al (2014) looked at the knowledge of anaphylaxis among Emergency Department staff in Korea. They suggested that a high proportion of doctors and nurses are able to recognise the signs and symptoms of anaphylaxis, but that there is a trend toward over-diagnosis. They felt, however, that the knowledge of treatment of anaphylaxis among nurses was moderate and can be improved (Ibrahim et al, 2014). Certainly, The Resuscitation Council UK (2017) suggests that despite there being clear guidelines about the management of anaphylaxis there is still confusion about the diagnosis, treatment, investigation and follow-up of patients who have had an anaphylactic reaction. The management, including medical interventions of anaphylaxis, will be discussed in the second part of this series.

Hanna et al (2014) suggested that although community health professionals follow The Resuscitation Council UK guidelines they also overestimate the risk of fatal anaphylaxis for food allergic children, which may result in increased levels of anxiety for parents (Hanna et al, 2014). Community staff including school nurses do, however, need to support parents as generally most anaphylactic reactions occur in the community, particularly food-related incidents (Muraro et al, 2014). There has to be a fine balance between over-estimating the risk and ensuring children and young people do receive the appropriate treatment. Certainly adolescents with severe allergies are at particular risk of severe and fatal anaphylactic reactions as adrenaline is under-utilised by this age group (Gallagher et al, 2011; 2012). The transition from childhood dependence to adult independence is possibly why this time period is of particular risk for adolescents with food allergy (Gallagher et al, 2012).

Conclusions

Anaphylaxis is life-threatening, particularly in children and adolescents (Grabenhenrich et al, 2016; Hompes et al, 2011; Simone et al, 2011). It is also very unpredictable and does not always have the same presentation (Dinakar, 2012; Grabenhenrich et al, 2016; Sheikh et al, 2008). Rates of anaphylaxis in children and young people also appear to have been rising in the UK (Tse and Rylance, 2009; Gibbison et al, 2012; Resuscitation Council, 2017). There is therefore a need to have a deeper understanding of anaphylaxis and how to correctly assess and diagnose it (Dinakar, 2012; Grabenhenrich et al, 2016). Certainly, nurses are in an ideal place to do this and to support children and young people to make informed decisions about their care and treatment, in partnership with guardians and their health professionals (NICE, 2011).

The second article will look at the management of anaphylaxis and the psychosocial impact of allergies in children.