Dr Samantha Walker and Annie Wing present an overview of allergies in children and young people

Samantha Walker RGN PhD Director of Education and Research Annie Wing RGN RSCN RHV BA(Hons) Associate Director of Education Education for Health, Warwick 

ABSTRACT  

An estimated 25% of the British population suffers from some form of allergic condition. Atopic dermatitis and food sensitivities are more common in infants and younger children, with hay fever (seasonal allergic rhinitis), perennial allergic rhinitis and allergic asthma developing throughout adolescence. Allergic reactions occur as a result of an interaction between allergen and mast cells via the antibody immunoglobulin E (IgE). Classic symptoms include itching, redness and swelling. These symptoms, and their time course, help the health professional to differentiate between allergic and nonallergic symptoms. Avoidance plays a part in management. Anaphylaxis is a medical emergency and recent guidelines recommend early use of epinephrine in patient with a severe allergic-type reaction. Journal of Family Health Care 2010; 20(1): 24-26

Key points   

_ Allergic diseases such as hay fever and allergic asthma are common, with an estimated 25% of the general population suffering from some form of allergic condition 
_ Atopic dermatitis and food sensitivities are more common in infants and younger children, with hay fever (seasonal allergic rhinitis), perennial allergic rhinitis and allergic asthma developing throughout adolescence
_ The term "allergy" is currently used to describe an immunological response to common airborne allergens or food/drug allergens; this is quite separate from "intolerance" which is an adverse reaction that does not involve the immune system
_ Anaphylaxis is a medical emergency and recent guidelines recommend early use of epinephrine in patients with a severe allergic-type reaction

Introduction   

Allergic diseases such as hay fever and allergic asthma are common, with an estimated 25% of the general population suffering from some form of allergic condition1. In children, the development of allergies often follows a defined pattern referred to as "the atopic march". Atopic dermatitis and food sensitivities are more common in infants and younger children, with hay fever (seasonal allergic rhinitis), perennial allergic rhinitis and allergic asthma developing throughout adolescence. For optimal management, it is important to recognise the systemic nature of allergic disease and the likelihood of symptoms manifesting themselves in different (but sometimes multiple) organ systems in the same children over a period of time. This article will discuss the various manifestations of allergic disease in children, diagnosis and management, and emphasise the importance of allergy training in improving UK allergy services.

Mechanisms of allergy   

Allergic reactions occur as a result of an interaction between allergen (e.g. grass pollen, peanut) and mast cells via an antibody, immunoglobulin E (IgE). The inhalation, ingestion or injection of allergen results in release of histamine from mast cells into the local and general circulation causing the characteristic symptoms of allergy in one or more organ systems. Allergic reactions vary, but classic symptoms include itching, redness and swelling. These symptoms and their time course (with immediate symptoms usually occurring within 15 minutes of exposure) mark the cornerstone of allergy diagnosis. At a simplistic level, this allows the health professional to differentiate quickly between allergic and non-allergic symptoms. 

Definitions  

The term allergy is currently used to describe an immunological response to common airborne allergens (aeroallergens) or food/drug allergens. This defines allergy as being quite separate from intolerance, which can be defined as an adverse reaction that does not involve the immune system. Examples of intolerance include migraine and irritable bowel symptoms which are seen in response to some foods. Atopy is described as a hereditary predisposition to develop allergic symptoms and is defined clinically as a positive skin prick test or specific IgE blood test to one or more common aeroallergens. It is important to remember that patients with a positive skin test/blood test to a particular allergen may not have symptoms on exposure to that allergen, and so a diagnosis of allergy cannot be made by the results of a skin test or blood test alone.

Diagnosis of allergy   

Allergy diagnosis is dependent on taking a detailed clinical history, and, in an ideal world, should be supported by the measurement of specific IgE, either by a skin prick test or by measurement of specific IgE in the peripheral blood. Invasive tests such as these can be distressing for young children and are not commonly used as a diagnostic tool in primary care. Successful management of allergic symptoms, however, does not depend on identification of an allergic trigger (exceptions include food and drug allergies) but on appropriate pharmacotherapy. Appropriate pharmacotherapy will in turn depend on the recognition of allergic and non-allergic symptoms and it is therefore important to differentiate between the two. 

Allergic skin diseases
Dermatitis 
 

Atopic dermatitis is an allergic skin disorder that commonly manifests itself in the first year of life. It is often the first indication of atopy in infants and is characterised by extreme itchiness due to dry, scaling skin. Triggers include food allergens and aeroallergens. The most common food allergens are egg, peanut, milk, soya, wheat and fish which account for nearly 90% of the foods that exacerbate dermatitis2,3. Dermatitis caused by common foods such as egg and milk is much more common in babies and young children, although aeroallergens such as pollens, house dust mites and animal dander can also exacerbate the condition. A careful history can help to identify allergens present in the diet or environment that are triggering the dermatitis. Management involves the removal or avoidance of any exacerbating factors such as infection, irritants and allergens where possible. Emollients are used to restore and maintain skin hydration as well as agents to reduce inflammation, e.g. topical steroids. Topical steroids should be applied when dermatitis is active (i.e. when skin is red and itchy), the aim being to use the weakest possible steroid to control the disease. The negative impact of atopic dermatitis on the child and family is associated with many quality of life issues such as sleep disturbance, low self-esteem and lack of confidence4,5.

Urticaria and angio-oedema  

Urticaria presents as whealing and erythema of the skin. It looks like a nettle rash or hives and is usually profoundly itchy. It is relatively common with 20% of the population estimated to have at least one episode in their lifetime. Angio-oedema is a deeper tissue swelling resulting from oedema in the dermis and subcutaneous tissues or the mucous membranes. Acute urticaria (lasting less than six weeks) and angio-oedema are often allergic in origin and commonly occur as a result of exposure to foods (e.g. peanuts, eggs, shellfish, milk), drugs (e.g. penicillin) and insect bites. Chronic symptoms, lasting for more than six weeks, are rare (around 0.1% of the population). Approximately 95% of cases remain idiopathic and are not usually associated with IgE-mediated hypersensitivity (although they are widely held to be by patients and some doctors alike). Treatment involves avoidance (where a clear trigger is identifiable), together with non-sedating antihistamines.

Allergic rhinitis  

Symptoms of allergic rhinitis include itching, sneezing, watery rhinorrhoea (runny nose), itchy eyes and nasal blockage. It is extremely common, its prevalence ranging between 15 and 30% depending on age, and is a particular problem in young children and adolescents where symptoms may lead to sleep disturbance, activity limitations and emotional problems6,7. Trigger factors include grass pollens, tree pollens, house dust mites and moulds, most of which are ubiquitous in the UK and largely unavoidable. Management depends on avoidance (where possible) and the regular administration of appropriate pharmacotherapy. Pollen avoidance is difficult and house dust mite avoidance almost impossible. It is noteworthy that there is no evidence of clinical efficacy for house dust mite avoidance in adult studies8. Symptoms usually respond to a combination of a daily topical nasal steroid and a non-sedating antihistamine. Prescription of a topical nasal steroid should always be accompanied by an explanation of device technique according to manufacturer's instructions. Patients should be followed up two weeks after the onset of symptoms to review effectiveness. First-generation antihistamines (e.g. chlorpheniramine) should be avoided because treatment with a sedating antihistamine can further compound the disruptive effects of rhinitis7.

Allergic asthma  

It has been observed that allergic rhinitis and asthma often co-exist in the same patients9 and recent guidelines10 have emphasised the importance of treating allergic rhinitis as well as asthma in such patients. Allergic triggers are common in children and can usually be identified from a good clinical history. Management is based on avoidance (where possible) and pharmacotherapy, preferably via the inhaled route according to the BTS/SIGN guideline for asthma11.

Food allergy/intolerance

Adverse reactions to foods can largely be divided into those known to have an IgE-mediated mechanism and those caused by non-allergic mechanisms. 
The challenge for the health professional is to distinguish between the two! This can be difficult but is necessary if appropriate treatment and recommendations for avoidance are to be given. Food allergy is a common manifestation of atopy in children affecting up to 8% of children under three years12, but only 2% of the adult population13. Some will "grow out of " their allergy with time but this is less common in those allergic to peanut, fish and shellfish. Around 10% of children with asthma and 30% of those with atopic dermatitis have an adverse reaction to food. Despite parental perceptions, relatively few foods cause food allergy. In fact nearly 90% of food allergies are caused by common foods such as milk, eggs or wheat. Diagnosis depends on a careful history and the performance of skin prick tests or specific IgE tests to suspected allergens. Food diaries may be helpful to eliminate food triggers. The only long-term treatment for food allergy and intolerance is to avoid the food. Children in whom food allergy is suspected, particularly those who have had a reaction involving throat swelling, tongue swelling and/or wheezing and who also have asthma should be referred to an allergy specialist or paediatrician.

Anaphylaxis 
Anaphylaxis is the severe IgE-mediated reaction which occurs following exposure to the relevant allergen in previously sensitised individuals. Common allergic triggers include peanuts, penicillin, insect venom and shellfish; non-allergic triggers include radiocontrast media used in X-ray-based imaging techniques, e.g. iodine and barium, and drugs used in general anaesthesia. Anaphylaxis is relatively rare although it is the most frightening manifestation of IgE-mediated allergy. This is because the reaction develops rapidly, is systemic, and is potentially fatal. In addition, it can be triggered by minute quantities of the relevant substance so that children and their parents can become extremely anxious about the possibility of anaphylaxis developing unexpectedly. Anaphylaxis is a medical emergency and a good outcome depends on its rapid recognition and appropriate treatment. Recent guidelines recommend early use of epinephrine in patients with a severe allergic-type reaction with respiratory difficulty and/or hypotension, particularly if skin changes are present14. Long-term management should include urgent referral to a paediatric allergy specialist for diagnosis and risk assessment. 
As with all allergies, avoidance is an important part of management. Children may find it reassuring to wear a bracelet or necklace giving details which will alert health care personnel of the cause of the reaction and recommended treatment. To give families and schools the details of self-help groups such as the Anaphylaxis Campaign (see Resources) may also be helpful.

The importance of allergy training   

Historically, knowledge about allergy in the community has been poor, although it is increasingly being recognised that training is an important component of high-quality care15. To establish the true impact of allergy training on patients' health, a recent landmark study compared the effectiveness of standardised allergy training (accredited by the Open University and delivered by Education for Health, see Further information) of primary health care professionals with usual care in promoting improvements in disease-specific quality of life in adults with perennial rhinitis4. 

The allergy study  

The study was a primary care-based trial comparing a six-month, distance-learning allergy module given to 20 general practitioners (GPs) and practice nurses from 12 general practices in the UK providing usual allergy care4. The training consisted of Education for Health's Allergy Course which contains 11 modules covering all aspects of allergic disease (see Further information). The doctors and nurses invited all adult patients with perennial rhinitis on their practice lists to participate; the 202 consenting patients were randomised to the training group (where they received care from a trained allergy health professional) or the control group (where they received receive routine care and a leaflet on rhinitis management). 

Results   

Disease-specific quality of life scores improved significantly in patients who consulted a trained health professional but not in those who received usual care. Health care professionals reported that the course was perceived to be of educational value in increasing self-assessed confidence and behaviour. The greatest improvements in confidence were reported in history-taking (100% of participants), skin prick testing (80%), allergy diagnosis (80%), treatment strategies (90%) and practical use of nasal spray devices (80%). The majority (75%) also reported an increase in prescriptions for nasal steroids. The allergy training module was well evaluated, the learning objectives being met by 100% of participants. Participants also reported that the module was relevant to their current practice and that the content was appropriate. Seventy-eight per cent considered that they had acquired new knowledge/skills. 

Implications
In this study, standardised allergy training was well evaluated by health care professionals and resulted in improvements in health-related quality of life in patients with perennial rhinitis. These findings highlight the importance of continued investment in professional education. (An example of how to make a case for training to present to managers and Trusts is shown under Further information.) 

Summary   

Allergic diseases can affect multiple organ systems within individuals over time. It is therefore important to ask children who present with one allergy symptom about the presence of others and treat them appropriately. Diagnostic and management guidelines are available for the majority of allergic conditions and health professionals should be familiar with their contents. One of the difficulties in allergy management is the lack of trained specialists. Recent evidence suggests that allergy training delivered to community-based staff improves quality of life in patients with rhinitis, and health professionals caring for allergic patients should be encouraged to access training where needed. 

Further information 
Education for Health
 

Registered charity no. 1048816 The Athenaeum, 10 Church Street, Warwick CV34 4AB Tel: 01926 493 313 E-mail: info@educationforhealth.org Website: http://www.educationforhealth.org.uk Education for Health is an independent education and research institution for health professionals, and is a merger of the National Respiratory Training Centre (NRTC) and Heartsave. It offers national and international training programmes accredited by the Open University. 

Allergy training  

Courses in allergy, including allergy training at diploma and degree level, are available from Education for Health. For details of the course described in the articles, see http://www.educationforhealth.org.uk/ For more details of all the allergy courses, please contact Laura Edwards, Allergy Education Co-ordinator, on 01926 838969.

Making a case for education and training  

Education for Health produce a toolkit entitled "How To Make Your Case For Education and Training". It contains evidence-based, disease-specific business proposals for nurses to use to establish their current levels of knowledge, understanding and experience. It also enables them to plan the development of their competencies within the framework of the health needs of their practice population in a way which is meaningful to the Quality and Outcomes Framework (QoF), the Knowledge and Skills Framework (KSF) and National Workforce Competencies. It can be accessed free of charge at: www.educationforhealth.org.uk/pages/businesscase.asp

Resources 
Anaphylaxis Campaign   

Registered charity no. 1085527 PO Box 275, Farnborough GU14 6SX Tel: 01252 546100 Helpline: 01252 542029 E-mail: info@anaphylaxis.org.uk Website: http://www.anaphylaxis.org.uk/home.aspx The Anaphylaxis Campaign provides support and information to all people at risk from life-threatening allergic reactions (anaphylaxis), particularly to foods, including peanut allergy. It aims to create a safe environment for all people living with allergy by educating the food industry, schools, preschools, colleges, health professionals and other key audiences. The Campaign's focus is on medical facts, food labelling, risk reduction and allergen management.

References 
1. Anderson HR, Ruggles R, Strachan DP et al. Trends in prevalence of symptoms of asthma, hay fever, and eczema in 12-14 year olds in the British Isles, 1995-2002: questionnaire survey. British Medical Journal 2004; 328(7447):1052-1053 
2. Sampson HA. John Glaser Lecturership. The role of food allergy and mediator release in atopic dermatitis. Journal of Allergy and Clinical Immunology 1988; 81(4): 635-645
3. Sampson HA, Albergo R. Comparison of the results of skin tests, RAST, and double-blind placebo-controlled food challenges in children with atopic dermatitis. Journal of Allergy and Clinical Immunology 1984; 74(1): 26-33
4. Su JC, Kemp AS, Varigos GA, Nolan TM. Atopic eczema; its impact on the family and financial cost. Archives of Disease in Childhood 1997; 76(2):159-162 http://www.educationforhealth.org.uk/ (accessed 28 September 2009)
5. Lawson V, Lewis-Jones MS, Finlay AY, Reid P, Owens RG. The family impact of childhood atopic dermatitis; the Dermatitis Family Impact Questionnaire. British Journal of Dermatology 1998; 138(1): 107-113
6. Juniper EF, Howland WC, Roberts NB, Thompson AK, King DR. Measuring quality of life in children with rhinoconjunctivitis. Journal of Allergy and Clinical Immunology 1998; 101(2 Pt 1): 163-170
7. Walker S, Khan-Wasti S, Fletcher M, Cullinan P, Harris J, Sheikh A. Seasonal allergic rhinitis is associated with a detrimental impact on examination performance in UK teenagers: case-control study. Journal of Allergy and Clinical Immunology 2007; 120(2): 381-387
8. Gøtszche PC, Johansen HK, Schmidt LM, Burr ML. House dust mite control measures for asthma. Cochrane Database Systematic Reviews (online) 2004 (4): CD001187
9. Rowe-Jones JM. The link between nose and lung, perennial rhinitis and asthma - is it the same disease? Allergy 1997; 52 (36 Suppl): 20-28. Review
10. Price D, Bond C, Bouchard J et al. International Primary Care Respiratory Group (IPCRG) Guidelines: management of allergic rhinitis. Primary Care Respiratory Journal 2006; 15(1): 58-70
11. British Thoracic Society [BTS] and Scottish Intercollegiate Guidelines Network [SIGN]. British Guideline on the Management of Asthma. Edinburgh: SIGN, revised edn June 2009. http://www.sign.ac.uk/pdf/sign101.pdf (accessed 28 September 2009)
12. Bock SA. Prospective appraisal of complaints of adverse reactions to foods in children during the first 3 years of life. Pediatrics 1987; 79(5): 683-688
13. Young E, Stoneham MD, Petruckevitch A, Barton J, Rona R. A population study of food intolerance. Lancet 1987; 343(8906): 1127-1130
14. Project Team of The Resuscitation Council (UK). Update on the emergency medical treatment of anaphylactic reactions for first medical responders and for community nurses. Resuscitation 2001; 48(3): 241-243
15. Upton J, Madoc-Sutton H, Sheikh A, Frank TL, Walker SM, Fletcher MF. National survey on the roles and training of primary care respiratory nurses in the UK in 2006: are we making a difference? Primary Care Respiratory Journal 2007; 16(5): 284-290