Diagnosing and Managing Common Allergies

Allergy Statistics (Allergy UK 2016) 615% increase in hospital admissions for anaphylaxis in 20 years, 1992-2012 (Turner et al, JACI, 2015) Food allergies doubled in last 10 years and hospitalisations caused by severe allergic reactions increased 7-fold (EAACI, 2015) By 2025 asthma will represent most prevalent chronic childhood disease (EAACI, 2014) Approx 30 allergy specialists in UK; 1 for every 700,000 sufferers

Allergy is a Systemic Disease Asthma Allergic Rhinitis Urticaria ALLERGY - A SYSTEMIC DISEASE Conjunctivitis Food Allergy Eczema

What is allergy? Allergy -is a disorder of the immune system Allergies -are inappropriate or exaggerated reactions of immune system to substances that in majority of people cause no symptoms Atopy -tendency to develop an exaggerated IgE response - i.e. a predisposition to develop allergic disease Allergy – the clinical expression of allergic symptoms Self explanatory stress the differences between these definitions These Terms are very frequently miss used

Allergy mechanisms

Vasodilatation (redness) Irritation of nerve endings (itching) Increased vascular permeability (swelling)

Histamine causes: Urticaria (itchy, red, swollen skin) Asthma (wheeze, cough) Rhinitis (sneezing, blockage) Anaphylaxis (itchy red rash, lip/tongue swelling, hypotension, wheeze etc)

Causes of allergy?

Diagnosing Allergy

History taking (1) Are the symptoms typical of allergy? Is there redness, itching or swelling? Is there an obvious allergic trigger? Remember occupation What is the relationship between allergen exposure and symptoms? Typical IgE-mediated allergic symptoms occur within approximately 15 minutes of allergen exposure Is there more than one organ system involved? IgE-mediated allergy tends to occur in more than one organ system

History taking (2) Is there a past history of allergic disease? True (IgE-mediated) food allergy more likely in adults who have seasonal or perennial hay fever or asthma or had asthma or hayfever as a baby Is there a family history of allergy? allergy is more common in children of (an) atopic parent(s) Remember allergic march (eczema → food allergies → rhinitis → asthma)

Is there redness, itching or swelling? Is there an obvious allergic trigger? Do symptoms occur within approximately 15 minutes of allergen exposure? Are there symptoms in more than one organ system ? Is there a past history of hay fever or asthma? Is there a family history of hay fever? If the answer is yes to one or more questions then investigate further…..

…and allergy tests are unlikely to be useful Is there redness, itching or swelling? Is there an obvious allergic trigger? Do symptoms occur within approximately 15 minutes of allergen exposure? Are there symptoms in more than one organ system ? Is there a past history of hay fever or asthma? Is there a family history of hay fever? If the answer is no to all the questions, then allergy is extremely unlikely…. …and allergy tests are unlikely to be useful

If ‘YES’ (i.e. a positive history of symptoms (itchy, red, swollen) within 15 minutes of exposure to an allergen) Is the suspected allergic trigger avoidable or treatable with an allergen-specific treatment (avoidance or immunotherapy)? [YES = foods, latex, bee/wasp venom, antibiotics, suxamethonium, grass pollen] [NO = house dust mites, cats, dogs, pollens, moulds] YES NO NO Do you need objective confirmation? Evidence-based avoidance Evidence-based pharmacotherapy YES SPT or sIgE test to suspected allergen only Follow up, device technique, adherence +ve history plus +ve test +ve history plus -ve test Evidence-based avoidance or allergen-specific treatment Either no action or further history-taking/ investigations

The Allergy March Incidence Age Allergic rhinitis Asthma Atopic dermatitis Incidence Food allergy 6/12 1 3 7 15 Age

Examination eyes ears nose skin height/weight chest general appearance

Triggers - Allergens House dust mites Pollens Animals Moulds Aeroallergens House dust mites Pollens Tree Pollens Grass Pollens Weed Pollens Animals Cats, Dogs, Horses etc Moulds Self explanatory Aero allergens - usual triggers for atopic asthma and rhinitis can be seasonal or perennial Pollen calendars Grass , tree and weed pollens all have different times of the year they are at their highest varies from different areas of the country and dependent upon the weather. Information available from met office and on web Cat dander - it’s the protein in the cats saliva that causes the problem. As the cat washes themselves the saliva dries on their fur it then becomes airborne. Very light allergen and tends to spread Research project demonstrated high levels on jumpers of school children who did not have cats, came from friends who had cats at home. Mould spores can trigger symptoms - Aspergillus, Clospridium, Alternaria alternate are the main ones.

Allergens Penicillin

The Nose - a forgotten organ?

Natural history of Allergic Rhinitis Onset: common in late childhood, adolescence and early adulthood Symptoms often wane in older adults but may present or persist at any age No apparent gender selectivity May contribute to other disorders such as sleep disturbance, fatigue and learning problems

Management of Allergic Rhinitis Allergen Avoidance Pharmacotherapy Immunotherapy

Asthma and allergies – what’s the link? Genetics – runs in families Rapid increase in the last 50yrs Is the change in lifestyle to blame? Research to see whether being exposed to allergens in early life will make someone more likely to develop asthma EXPLAIN THAT: Asthma often runs in families. If one or both parents have an allergic condition such as asthma, hay fever or eczema, their child is more likely to develop asthma However the increase over the past 50 years suggest that environmental factors must play a part Is suggested that the increase in allergies has followed ‘Westernisation’ as countries and communities have modernised, the changes in lifestyle (diet, housing and hygiene) have lead to a increases in allergy

Pollen - What to do? See GP or nurse before season starts to review asthma treatment and add on hay fever medicine Check pollen forecast Keep doors and windows closed mid morning/early evening – don’t take washing in at those times Splash eyes with cold water Wear wraparound sunglasses EXPLAIN measures to combat pollen

Pharmacotherapy Medications used to treat allergic rhinitis: Antihistamines Decongestants AH-D combinations Corticosteroids Mast Cell stabilizers Anticholinergics Antileukotrienes 27

Actions of various nasal preparations Sneezing Itching Rhinorrhoea Congestion Antihistamines +++++ ++++ +++ Anticholinergics Corticosteroids Decongestants + Mast cell stabiliser LTRAs +++ ++ ++++ 28

A form of food intolerance in which there is evidence of an abnormal immunological reaction to food Food Allergy Royal College of Physicians 1994

Adverse reactions to food ALLERGY INTOLERANCE AVERSION Immune system alteration Pharmacological Metabolic Toxic Idiosyncratic Dislike

Allergic Food Reaction Non-allergic Food Reaction

Common food triggers

Legumes

Nuts

Cross reactivity

Allergy diagnosis: tests to confirm allergic sensitivities Specific IgE blood tests Skin prick tests · SPTs and specific IgE tests will be discussed in the next session Patch tests are used in hospital settings to diagnose contact dermatitis and will not be discussed in this workshop May be useful to mention the difference between SPT and Patch testing as people do seem to get these 2 tests confused.

Specific IgE Blood test which measures specific IgE What is it? Blood test which measures specific IgE Sent to laboratory (local/regional) Results not available immediately Commonly known as RAST test (Radio allergo sorbent test) Possible to test > 400 different allergens Advantages – Completely safe High degree of specificity can be as high as 90% for aeroallergens High degree of precision and standardisation Preferable to allergen provocation when a confirmatory test is required results presented in absolute values or grade out of 6 Not influenced by any concurrent drug therapy Can be performed where there is widespread skin disease Disadvantages – Not immediate for patient to see Results not immediately available for Health Care Practitioner Expensive

Interpretation of results A positive result AND a positive history confirms relevance of the specific trigger to that patient A positive result on its own is meaningless (i.e. does not mean the patient will get symptoms on exposure; 80% of people who are sensitised to peanut will not get symptoms on exposure*) Cannot be used to ‘screen’ people who have no allergy history e.g. take a child who has not previously avoided peanuts (so exposure likely) but whose parent is concerned about allergy because a sibling is allergic. If you test for peanut, it’s positive and you advise avoidance you are condemning that child to a lifetime of avoidance without knowing if they’ll ever get symptoms on exposure….if you tell them to ignore the test result and they get a bad reaction they might sue you…….so, only test things you suspect are a problem or that people have had a reaction to! * Nicolaou M et al J Allergy Clin Immunol 2010;125:191-7

Next steps If the history and the test result is positive: either confirm diagnosis and manage in primary care refer for specialist opinion and/or management advice If the history and test results don’t match, or you’re not sure: Refer to an allergy specialist

Think about the impact allergic disease has on children & adults What can we do as HCP’s to improve diagnosis in children and adults? How can we raise awareness? How can we ensure appropriate treatment and management?

Time for reflection