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Allergy, intolerance or something else?

Allergy, intolerance or something else?. Apologies. Evidence base is small Simple Slanted towards food allergy. Main workload. Definite allergy e.g. Nuts, Seasonal allergic rhinitis. Confirm diagnosis, help management.

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Allergy, intolerance or something else?

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  1. Allergy, intolerance or something else?

  2. Apologies • Evidence base is small • Simple • Slanted towards food allergy

  3. Main workload • Definite allergy e.g. Nuts, Seasonal allergic rhinitis. Confirm diagnosis, help management. • Possible allergy .e.g. Urticaria, rhinitis. Obtain diagnosis, help management. • “I want an allergy” e.g. IBS, CFS. Exclude allergy, refer on if appropriate.

  4. Allergy, intolerance or hypersensitivity? Allergy • IgE, histamine, leucotrienes, mast cells, immediate, largely reproducible. • Urticaria, eczema, itch, rhino-conjunctivitis, abdominal pain, D&V, angioedema, bronchospasm, hypotension • Treat with information, avoidance, block histamine, save lives with adrenaline, desensitisation.

  5. Allergy, intolerance or hypersensitivity? Intolerance • Foods. Mechanism not known, effects delayed up to 48 hrs. • Symptoms can be like true allergy but less severe plus the bug bears of the consulting room: tiredness, bloating, headaches. • Treat with avoidance, Na chromoglycate.

  6. Allergy, intolerance or hypersensitivity? Hypersensitivity Reactions to pharmacologically active compounds. Classic example is salicylates and related compounds (e.g. benzoates). Also sulphites and tyramine. Often flushing and palpitations as well as typical allergic symptoms and the “fringe”: ADHA, parathesia, headcahes etc. Avoid, anti-leucotrienes, desensitisation (NSAIDs).

  7. UK deaths from anaphylaxis, 1992-98 Deaths under age of 12 are unheard of in UK. Nearly all deaths from food allergy occur in brittle asthmatics.

  8. Angioedema Causes Investigation Treatment

  9. Causes Infection Obvious, rarely over looked but minor infection may trigger HAE/AAE. Idiopathic/Physical Really a diagnosis of exclusion. Heat, cold, pressure, stress, infection. Mast cell degranulation triggered by anti-IgE receptor antibodies in 60% of cases. Association with other autoimmune disease e.g. thyroid, adrenal, IDDM.

  10. Causes Drug induced ACE inhibitors 25-58% of cases of angioedema. Increased incidence with age, non-atopy, and possibly Afro-Carribean origin. Throat more than face, onset in 4 weeks but up to 4 years ACE II as well (but rare). Not Mast cell degranulation.

  11. Causes Drug induced Asprin and NSAIDS Usually rhinitis, asthma, possible food intolerances. Others Fibrinolytic agents, oestrogen.

  12. Causes Allergic Usually history of atopy (hayfever, asthma, eczema, drugs, animals, foods, latex) or FH. Itch, urticaria, wheeze. Lip tingling, tongue swelling previously? When, where, what were they doing? Exercise induced anaphylaxis.

  13. Causes Aquired Angioedema (AAE) Autoantibody to Cl-inh associated with lymphoma, CCL, myeloma, SLE, Ca. Hereditary Angioedema (HAE) FH, no itch, “painless”, triggered by trauma, infection, stress.

  14. Investigation Treat first (I.m. adrenaline) Specific IgE to common if no clues-peanut, egg, HDM, wasp/bee, grass. Mast cell tryptase. ASAP, 3hrs, 24 hrs. C3C4: C4 low in HAE and AAE (also null alleles). C1-inh level and function if C4 low or STRONG clinical suggestion.

  15. The tricky patient with urticaria • The only potentially fatal sub-group: ladies with affected faces. • Dermographism, pressure, heat, cold, stress, pre-menstrual - think idiopathic/physical. • Worse in bed - HDM or physical. • Aspirin or NSAID? • FH

  16. The tricky patient with urticaria • Check IgE to HDM, mixed foods (egg, milk, wheat, cod, soya, peanut). • Thyroid antibodies, TSH. • ANA, ENA if suspicious of CTD.

  17. The tricky patient with urticaria • Piriton. Syrup rapidly absorbed so OK for acute. Impaired learning, driving etc even if not drowsy so not good for chronic use. • Desloratidine, levoceterizine, fexofenadine. Safe, first 2 up to 15mg/day, fexo 180mg. • Acrivastine rapidly absorbed but need tds. • Cimetidine, ranitidine - H2 blockers • Montelukast • Cyclokapron (eyes) • Danazol (warn) • CyA, Azothiaprine, prednisolone.

  18. Drug allergy • History/examination as for typical allergy vs fixed drug eruptions vs viral rash • OK ish for penicillins. History, IgE, SPTs. • Multiple antibiotic allergy - a headache. Try to determine most and least likely to cause a reaction. • Multiple drug allergy - Ouch! Hope for lactose intolerance. • Anaesthetic reactions. Usually clear cut. • Local anaesthetic reactions. Usually faint or adrenaline leakage.

  19. Sometimes I can eat it… • Salicyate • Multiple factors • Exercise • Cooking • Poisoning (scombroid) • Contamination

  20. I want an allergy test…(I’ve had an allergy test….) • Negative IgE or SPT usually means no allergy. Does not excludetriggers for eczema, intolerance. • Positive tests help confirm suspected allergen. • Screens “in case” are to be discouraged (FH of nut allergy to be excepted). • Good dietician. • Own challenge if not suggestive of typical allergy or severe symptoms.

  21. Summary • Make sure the patient understands the simple things: Allergy can kill if “internal”, merely a nuisance if “external”. • Avoidance leads to “weakening” of the allergy as well as no symptoms. • Idiopathic urticaria/angioedema is frustrating and worrying for patient and Dr. • ASK FOR ADVICE Jonathan North 0121 507 4250 Fax: 0121 507 4567 Jonathan.North@swbh.nhs.uk

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