The relationship between asthma and food allergy Dr Deborah Marriage Lead Nurse, Paediatric Allergy

Session aims Whistle-stop tour of IgE mediated food allergy Anaphylaxis Recognise increased risk of anaphylaxis in children with FA & asthma Examine patient perceptions of the impact of foods on asthma Consider a potential causal relationship between FA & asthma? Examine the effect of co-morbidity on asthma Identify risk factors Think about management & treatment options

Definition of IgE-mediated allergy ‘An exaggerated sensitivity to a substance (allergen) not normally considered to be harmful, that is inhaled, swallowed or injected, or that comes into contact with the skin or eyes’.

What are the common culprits?

League table of food allergens (90% of reactions are caused by 7 foods)

Anaphylaxis ‘An acute, severe, life-threatening allergic reaction in pre-sensitised indivicuals, leading to a systemic response caused by the release of immune and inflammatory mediators from basophils and mast cells. At least 2 organ systems are involved’

Allergic asthma The airway response to histamine is more sensitive in asthmatics Allergen recognition leads to mast cells mediator production, ↑ histamine levels, inducing early phase bronchoconstriction and acute asthma symptoms Late phase response due to chemotactic factors released by mast cells & inflammatory cell influx 4-6 hours after initial episode, eosinophils & neutrophils accumulate in the lungs causing oedema, tissue destruction and mucus production

Risk of anaphylaxis Children with FA and asthma are at increased risk for severe anaphylaxis, including fatal events This is compounded if asthma is poorly controlled Food-allergy related fatalities 25 patients with sufficient information available 24 had asthma Is this a causal relationship or coincidence? Bock SA et al (2001) Fatalities due to anaphylactic reactions to foods. JACI

Asthma & Peanut Allergy Symptoms of most recent reactions

Reaction Severity 3 Year UK Survey 1998-2000 (McDougall, Arch Dis Child 2002)

UK Mortality data 8 paediatric deaths in 8 years (1990-1998) - 4 milk - 2 peanut (>13 years) - 2 pretreated with Epipen - 1 adrenaline overdose (iv by medic) - Asthma strongly associated 6 severe / 49 near fatal reactions - 10 peanut - 14 tree nuts  Risk of death 1:800 000/yr (Hourihane, ADC 2002)

What is the role of FA in asthma? Several studies examine the role of FA in asthma development Co-existence increases the severity of both disorders Risk even greater when food allergy is multiple or severe

Patient Perception

Patient Perception 20-60% people report food as a trigger for asthma but only 2.5% react to DBPCFC Australian survey 156 asthma clinic patients 73% believed food induced their asthma symptoms 61% had attempted to modify their diet 79% of those reported improved asthma control (Woods PK et (1996) Patients’ perceptions of food-induced asthma. Aust N Z J Med)

Effect of FA upon asthma morbidity FA independently associated with ↑asthma Children with FA & asthma ↑ asthma morbidity than asthma alone Higher rates of hospitalisation Higher oral steroid requirements ↑ rate of severe asthma exacerbations (OR 6.) ↑ rate of life-threatening asthma Gonzalez-Perez, A et al (2010) Anaphylaxis epidemiology in patients with and without asthma: a UK database review JACI Roberts GC et al (2003) Food allergy as a risk factor for life-threatening asthma in childhood. JACI Wang J et al (2005) Food allergen sensitization in inner-city children with asthma. JACI Savage JA et al (2007)The natural history of egg allergy. JACI Liu AH (2010) National prevalence and risk factors for food allergy and relationship to asthma. PAI

Asthma Management Options Do children with FA & asthma require more aggressive asthma management than asthmatics without FA? ↑ FENO ↑ sputum eosinophils In adults, ↑FENO, Airway Responsiveness (AR) & circulating eosinophils associated with + SpIgE to 6 foods Caffarelli C (2012) Hydrogen peroxide in exhaled breath condensate in asthmatic children during acute exacerbation and after treatment. Respiration Patelis A (2014) Aeroallergen and food IgE sensitization and local and systemic inflammation in asthma. Allergy

What is the link between FA & Asthma? Association between FA & Asthma stronger when subjects stratified for concurrent aeroallergen sensitisation Penard-Morand C et al (2005) Prevalence of food allergy and its relationship to asthma and allergic rhinitis in schoolchildren. Allergy

Is greater atopy merely associated with severe, persistent, earlier-onset asthma and food sensitisation or is there a direct causal relationship?

Food allergy & Prediction of asthma development Allergic March IgE food sensitisation linked with wheeze at age 7 Multiple studies have confirmed the risk for asthma is greater in infants with eczema, multiple food sensitisation & filaggrin mutation

Food allergy risk factors for asthma

Egg allergy Seems to be more relevant that allergy to milk +SPT to egg in 1st year of life is predictive of adult asthma (OR 10.7) Children with an atopic family history or wheezing who have egg allergy are more likely to develop asthma Tariq SM et al (2000) Egg allergic in infancy predicts respiratory allergic disease by 4 years of age. PAI Gaffin JM et al (2011) Tree Nut Allergy, Egg Allergy, and Asthma in Children. Clin Pediatr.

Milk allergy Milk allergy at 7/12 associated with ↑ BHR and FENO at age 8. Sever asthma may be a predictor for persistent CMPA. Saarinen KM et al (2005) Clinical course and prognosis of cow's milk allergy are dependent on milk-specific IgE status. JACI Malmberg LP et al (2010) Cow's milk allergy as a predictor of bronchial hyperresponsiveness and airway inflammation at school age. CEA

Severe allergens Some allergens are more commonly linked with severe allergic reactions than others

Less obvious manifestations

When to suspect FA in asthmatic children Acute life-threatening asthma with no identifiable triggers Highly atopic children with severe persistent asthma resistant to therapy who give poor clinical histories (ie children in care)

Airborne food allergens Inhaled food molecules can provoke severe reactions in allergic children eg cafes, fish market Caused by cutting, boiling or steaming Some clinical reactions (esp fish or shellfish) may be more severe than when taken orally Some may only cause reactions when inhaled DPIs containing lactose do not usually cause reactions but in severe milk allergy and asthma chest tightness, ↓BP and FEV1 have been reported from some lots of Seretide

Food-dependent, exercise-induced anaphylaxis (FDEIA) Food intake or exercise alone does not induce symptoms Anaphylaxis triggered by exercise only when child ingests a particular food (often wheat) Not always reproducible; may be mild or strenuous exercise Half present with cough, chest tightness or wheeze reduction in FEV1 on those without respiratory symptoms

Implications for practice FA & asthma co-exist in many children Increased risk of food anaphylaxis in asthmatic children FA children conversely also likely to have severe asthma Accurate diagnosis of both FA & Asthma essential Increased awareness of the heightened risks of having both conditions + good family education can lead to improved outcomes Allergy Action Plan Personalised Asthma Action Plan Training for any AAI prescribed Written supporting information (Allergy UK; Anaphylaxis Campaign)

Emergency Medication

Conclusion FA & Asthma places children at greater risk for morbidity and mortality, particularly if asthma in uncontrolled Heightened awareness of the relationship between them is important & recognition may improve treatment and prevent severe reactions Consider FA in children with life-threatening asthma Such children require AAIs (with training!) A multi-faceted approach leads to optimal care Family education is paramount

Thank you!