Diagnosis of allergy

• Allergies are increasing worldwide
• Allergies are an abnormal immune response (hypersensitivity) to a harmless stimulus
• Laboratory testing is useful for diagnosis and treatment
• Hay fever is a type of allergy
• Immunotherapy was discovered for allergies
• IgE is involved in allergies
• The immune system can go wrong in allergies
• Immune system can fight harmless substances in allergies
• Autoimmunity is when the immune system fights its own body
• The pathogenesis of allergy involves various cells and cytokines
• Different types of hypersensitivity reactions in allergies: Type I, Type III, Type IVa, Type IVb, Type IVc, Type V, Type VII
• Allergy symptoms include conjunctivitis, rhinitis, oral allergy syndrome, angioedema, asthma, anaphylaxis, urticaria, dermatitis
• Atopy is a predisposition to develop allergic diseases
• Allergen burden and symptom threshold are important in allergies
• Diagnosing allergies involves history, blood IgE test, skin prick test, examination, BAT/Lymphocyte stimulation test, provocation test
• Allergy history includes onset, course, aggravating factors, relieving factors, drug and food sensitivities, family history, previous medical conditions, previous investigations, previous treatment
• Diagnostic tests for allergies: IgE Blood testing, Specific IgE testing, Mixed-allergen tests, PAMD, Skin prick testing, Provocation/challenge testing
• Molecular allergy diagnostics involve measuring IgE to specific allergen molecular components for diagnosis and management
• Allergen nomenclature includes genus, species, and order of discovery
• Cross-reactive components in allergies are shared protein families among different allergen sources
• Cross-reactive components include CCD, Profilin proteins, PR-10 proteins, Lipid transfer proteins, Storage proteins
• Clinical utility of allergy component testing: avoid uninformed dietary advice, identify severe allergens, predict outgrowing of allergies, improve patient selection for AIT, provide guidance on pet selection, detect allergy syndromes
• Identify allergens associated with severe symptoms
• Identify children likely to outgrow a food allergy
• Improve patient selection for AIT
• Provide appropriate guidance on pet selection
• Detection of allergy syndromes
• Distinguish between cross- and co-sensitization
• Investigate anaphylaxis where the triggering allergen is unknown
• Avoid uninformed dietary advice
• Avoid uninformed dietary advice for Milk:

  • Bos d 4 + Milk Bos d 4 and Bos d 8
• Avoid uninformed dietary advice for Tomato:

  • PR-10 + Apple LTP + Concentrated in peel
• Avoid uninformed dietary advice for Can f 4:

  • Dog Can f 5 + ALEX 2 multiplex IgE test
• Patient selection for AIT for Bee:

  • Api m 1 and Api m 10 + Wasp Ves v1 and Ves v 5 + Eligible for AIT
  • True wasp allergy
  • True bee allergy
  • CCD
• Venom allergies:

  • Stings from bees, wasps, and other insects can cause a transient local reaction
  • Anaphylactic reactions occur in 0.6% of children and 3% of adults
  • Bee venom is the leading cause of fatal anaphylaxis
  • Risk factors for stings include occupations, hobbies, climate, temperature, and insect behavior
  • Reactions can be local, large local, or systemic
• Systemic reactions:

  • Most episodes develop rapidly
  • Resolves with treatment
  • A few cases may have a biphasic course with recurrence of symptoms hours later
• History for venom allergies:

  • When, where, environmental activities, time delay, which insect, stinger, symptoms, treatment, medication, delayed reaction, previous reactions
• Diagnosis for venom allergies:

  • Diagnostic testing should be done on ALL patients with a systemic reaction
  • Not recommended for local or large local reactions unless it becomes progressively larger or risk for multiple or recurrent stings or over-anxious patient
• Blood tests for venom allergies:

  • Serum tryptase level: Within one to four hours of reaction and follow up level at 24-48 hours to determine the baseline
  • Elevated level above baseline confirms anaphylaxis
  • Higher baseline level predicts the risk of a future severe reaction
  • Specific IgE to bee venom: 85% sensitivity
  • Cross-reactivity on bee venom IgE testing may occur between bee venom and wasp venom
• Management for venom allergies:

  • Remove venom sac
  • Mild local reactions: Analgesia and cold compresses
  • Large local reactions: elevation of limb, antihistamines, anti-inflammatories, short course of corticosteroids
  • Mild systemic reactions (only cutaneous): Antihistamines and observation
  • Severe systemic reactions: Intramuscular Adrenaline with anaphylaxis protocol