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Allergy in General practice Naomi Oliver Why? • Common presentation in general practice • Hopefully not covered recently during a VTS session • Recently had an FGM presentation Learning objectives • To be aware of the indications for testing for food allergies • To become familiar with allergy tests • To have a better understanding of the Management of allergic and contact Dermatitis • To have a better understanding of the Management of Allergic Rhinitis • To have a better understanding of the Management of Urticaraia • To have a better understanding of the Management of Anaphylaxis in primary care • Referral guidelines to secondary care for allergic conditions Curriculum mapping: • • • • 3.03 Care of Acutely Ill People (Anaphylaxis) 3.15 Care of People with ENT, Oral and Facial Problems 3.19 Respiratory Health 3.21 Care of People with Skin Problems An interesting case for discussion • 29 year old female • Haematology ward, being treated for an unknown haematological malignancy • PMH: Nil, allergies: Anaphylaxis to nuts • Bleeped at 5.30pm to re-site cannula for 2nd unit of blood to be given • 6pm (ish) fast bleeped to ward, anaphylactic reaction • Why did this occur? Allergic transfusion reaction • Caused by the passive transfer of peanut antigens in the blood products • The major peanut antigen Ara H2 is resistant to digestion • Well documented cases in literature of patients with known anaphylactic reactions particularly to peanuts reacting after receiving blood products after recent digestion of peanuts from donor. • Considerations for future donors? Screening questionnaires of food recently eaten? Period of refraining from eating nuts before donating blood? What is an ‘allergy’? “ Hypersensitivity caused by exposure to a particular antigen (allergen) resulting in a marked increase in reactivity to that antigen on subsequent exposure. Sometimes this may result in harmful consequences” 1 Types of allergic reaction2: Food allergies: • Very common, studies suggest levels of food allergies appear to be increasing. • NICE guidelines 2011. Differentiate between IgE mediated and non IgE mediated. IgE mediated Non IgE mediated Pruritis, erythema, diarrhoea and abdominal pain are common to both types. Pruritis, erythema, diarrhoea and abdominal pain are common to both types. Acute urticaria - localised or generalised. Acute angio-oedema Oral itching, nausea, vomiting. Colicky abdominal pain. Nasal itching, sneezing, rhinorrhoea, allergic conjunctivitis. Cough, shortness of breath, wheezing and bronchospasm (or history of asthma). Atopic eczema. Gastro-oesophageal reflux. Infantile colic. Stools: loose and/or frequent, blood and/or mucus. Constipation. Perianal redness. Pallor and tiredness. Faltering growth. Food aversion or avoidance Food allergies continued • If you suspect that the allergy is IgE-mediated offer a skin prick test or blood tests for specific IgE antibodies to the suspected foods. • If you suspect that the allergy is non-IgE-mediated allergy eliminate the suspected allergen for 2-6 weeks, then reintroduce. Allergy tests: Skin Prick testing Radioallergosorbent test Skin patch testing (RAST) Most commonly used test. Quick and easy. Drops of diluted antigen placed on the skin which is then pierced using a sterile needle. Can be interpreted after 1530mins. Determines the amount of IgE that reacts with a suspected allergen. Results are given in grades 0 negative to 6 strongly positive. Up to 40 potential allergens are placed on the back. Patches removed 48 hours and results interpreted. Useful for testing food allergies and pollen. Theoretical risk of anaphylaxis. Need to refrain from using antihistamines for at least 5 days. Useful for food allergies, pollen and venoms. Good to use in patients who are currently taking antihistamines or have skin conditions such as eczema Useful for contact dermatitis. Allergy tests continued: Allergic contact dermatitis • Most commonly caused by contact with substances such as Nickel, cosmetics, rubber chemicals and dyes • Clinical features: Develops after 1-2 days after exposure • Skin inflammation, weeping, vesiculation. In chronic stages can cause dryness, scaling and fissuring. Most common sites affected ear lobes, nape of neck and wrist. • Clinical diagnosis but can use patch testing. • Management: Avoidance, topical corticosteroids, ointments +/- oral antihistamines Allergic contact dermatitis versus irritant dermatitis? Primary irritant: • No previous exposure required • Everyone susceptible to irritant dermatitis. • Non allergic reaction, due to contact with skin irritants like acids and alkalis • Most typically seen after using a hair dye which causes a weeping eczema. • Management: Avoidance of trigger and topical steroids Contact dermatitis: Allergic rhinitis • Seasonal: caused by grass and or tree pollen. Symptoms occur at the same time every year. • Perennial: caused by house dust mites. Symptoms occur throughout the year • Occupational: caused by allergens at work. Symptoms often improve at weekends and during leave. • Clinical features: rhinorrhoea, nasal blockage, sneezing, itching eyes, nose and ears, wheeze, fatigue, malaise • Clinical diagnosis based on history. However RAST/skin prick testing can be used for specific allergens like dust mites and grass/tree pollens. Allergic rhinitis management: Medication Examples: Antihistamines: oral antihistamines are effective first-line drugs which relieve ocular symptoms, nasal irritation, rhinorrhoea and sneezing but has limited effect on nasal congestion Cetirizine Loratidine Fexofenadine Corticosteroids: in severe cases systemic steroids, in the form of a course of low dose oral steroid, may be used e.g. prednisolone up to 20 mg daily for up to 5 days. Prednisolone nasal corticosteroids - used as first line therapy in moderate to severe allergic rhinitis. Fluticasone Betamethasone Leukotriene receptor antagonists: used in addition to antihistamines and nasal corticosteroids. Monteleukast Anticholinergic agents: intranasal ipratropium used in watery rhinorrhoea Intranasal decongestants (short term) ipatropium Referral criteria for Rhinitis and immunotherapy: • Persistent symptoms despite maximal oral and topical therapy. Symptoms still persistent for more than 6 weeks with using intranasal steroids- REFER • Immunotherapy (increasing amounts of allergens are administered subcutaneously to an allergic person to minimize the allergic reaction following exposure to that particular allergen) • • • • • with persistent moderate to severe symptoms in spite of treatment who needs systemic corticosteroids with coexisting diseases like sinusitis, asthma poor response to nasal corticosteroids in 1-3% of patients, moderately severe systemic reactions can be seen Urticaria AKA Hives, nettle rash or wheals. • Acute: < 6 weeks of continuous activity • Chronic: > 6 weeks of continuous activity. • Can be categorised by cause: physical (mechanical, thermal), contact (allergens or chemicals),urticarial vascultitis, and angio oedema without wheals • Common causes: Food, drugs (Aspirin, NSAIDs, opiates), infection, emotional stress • Urticaria may be associated with: SLE, viral hepatitis, leukaemia and lymphoma, infections and hereditary angioedema • Careful history to elicit cause. Ix may be required (FBC, ESR, TFTs, Autoantibody screens Urticarial management: • General principles: Avoidance of triggers e.g.. Stress, alcohol and medication • Cooling anti-pruritic treatments (calamine lotion, aqueous cream) • Medication: First line: cetirizine, loratidine and fexofenadine. Can use a sedating anti-histamine if sleep is also an issue. • Leukotriene receptor antagonists can be used in addition to antihistamines • Oral steroids not routinely recommended however can be used in the short term where patients are not responsive to antihistamines • Immunomodulating therapy: Ciclosporin, and tacrolimus for severe urticaria refractory to treatment Referral to secondary care: A patient should be considered for referral to secondary care (immunologist or dermatologist) , where: • Uritcaria with angioedema not involving the airway • Food or latex allergy causing severe acute urticaria • Chronic persistent urticaria refractory to treatment and symptoms which are persistent despite avoidance of known triggers • Vasculitic uriticaria Urticaria Anaphylaxis Life threatening type 1 hypersensitivity reaction. Most common precipitants include food (peanuts, almonds, fish, milk), medications( antibiotics, heparins, contrast media) and venoms. Clinical presentation: sudden onset rapidly progressive symptoms, life threatning airway, breathing or circulatory symptoms and skin or mucosal symptoms. (Hypotension, stridor, wheeze, urticaria, abdominal pain, nausea, pruritius) However in children presentation may be rather vague to include pallor, limpness and apnoea. Management in primary care: • Removal of allergen if possible • ABCDE • Administer adrenaline! 1in 1000 IM injection (dose can be repeated every 5 mins if no improvement) • call ambulance Children (0 to 6 years) Children (6-12 Adults (12 years) years +) 0.15mls/150 micrograms 0.3mls/300 micrograms 0.5mls /500 micrograms Confirmation of anaphylaxis • Diagnosed clinically however can be confirmed by measuring mast cell tryptase. Levels peak immediately during reaction and up to 4 hours, 2nd level to be taken at 1-2 hours. • ALL patients should go to hospital. Why? Delayed second reaction. • After emergency treatment for suspected anaphylaxis, offer patients a referral to a specialist allergy service and an IM adrenaline pen as an interim measure before their appointment Summary: • Common presentation in primary care • Management should incorporate both prevention and treatment of active symptoms • Consider referral to secondary care for symptoms refractory to treatment • Steroids are not the mainstay of treatment and should only be used in certain circumstances • All patients following anaphylactic treatment should go to hospital. Be aware of delayed secondary reactions! Questions References: • • • • 1.http://medical-dictionary.thefreedictionary.com/allergy 2http://philschatz.com/anatomy-book/contents/m46566.html GP notebook: Allergic rhinitis, contact dermatitis, Anaphylaxis Emergency treatment of anaphylactic reactions. Guidelines for healthcare providers. Working Group of the Resuscitation Council (UK).2008 • NICE (December 2011). Anaphylaxis: assessment to confirm an anaphylactic episode and the decision to refer after emergency treatment for a suspected anaphylactic episode. • https://www.nice.org.uk/guidance/CG116/chapter/1Guidance