Chapter 11: Allergic Conditions in Otolaryngology Patients Flashcards
Common conditions involving the nose and sinuses
Adverse immune reactions
Allergies
Type of allergy which is mediated by reagin-type antibodies
Atopy
Main immunoglobulin involved in the production of atopic conditions
IgE
Involve and antibody, usually IgE, attached by the Fc portion to a cell containing mediators or their precursor
Antibody cell-associated reactions (reagin, cytophilic, anaphylactic antibodies)
Asthma
Anaphylaxis
Urticaria
Seasonal rhinitis
Antibody cell-associated reactions
Involve an antibody, usually of the IgG and IgM variety, interacting with an antigen that is part of or associated with the cell wall
Complement-dependent can cause damage, stimulation or blockade
Antigen cell-associated reactions (cytotoxic, blocking and stimulation antibodies)
Damage to cell
Rh-positive
Penicillin hemolytic anemia
Autoimmune thrombocytopenia
Stimulation
Thyrotoxicosis
Blocking
Myasthenia gravis
Insulin dependent diabetes
Bronchial asthma
Rhinitis
Involve interaction of the antigen and antibody independent of the cell, activating the complement and other amplifying systems–>adverse reaction
Eg. Serum sickness, PSGN,
Antigen-Antibody reactions and cell-independent reactions (arthus reaction, immune complex)
Antigen interacting with T lymphocytes leads to the release of various mediators
Eg. Dermatitis, transplantation reactions
Cell-mediated reactions
Main in vivo method to identify IgE or reaginic antibody
Occurs within minutes after introduction of the allergen
Skin testing
More sensitive but more likely to produce systemic reactions in highly sensitive individuals
Intradermal testing
Most popular way to quantify IgE
Radioallergosorbent test (RAST)
Indications for performing the RAST and the histamine release assay
- Situations in which the patient cannot be skin rested such as the presence of dermatographism, dependence on medication that interferes with skin testing, extreme youth and age when skin testing is difficult to perform and interpret, previous extreme sensitivity to the test allergen
- Need to confirm the significance of a positive skin test
- Strong history of allergen sensitivity but a negative skin test