Term
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Definition
| Inherited tendency to react to common environmental allergens with the production of IgE |
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Term
| What four pathologies can result from atopy? |
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Definition
allergic rhinitis,
allergic asthma,
atopic dermatitis,
allergic gastroenteropathy |
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Term
| What is the difference between intolerance and allergy? |
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Definition
Allergy is actually IgE mediated, intolerance is not
Ex. allergic to milk means an allergy to milk protein (casein), intolerance to milk means a lack of lactase |
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Term
| Is all IgE-mediated disease atopic? |
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Definition
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Term
| Is serum IgE elevated in an atopic patient? |
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Definition
| No, because it binds to mast cells. Tissue IgE is probably elevated. |
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Term
| What are the odds of an individual being atopic? |
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Definition
About 75% if both parents and 50% if one parent is atopic
10-30% of population exhibit atopy |
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Term
| How do helminthiasis (parasitic infections) influence atopy? |
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Definition
| In areas of the parasitic infections are endemic the mast cells and basophils may be saturated with anti-parasitic IgE and prevent involvement of IgE to other allergens |
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Term
| List physical characteristics of allergens. |
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Definition
Proteins
Often proteases
Favors activation of IL-4
Low molecular weight
Low dose needed
High solubility
High stability (long half life)
Bind to MHC II |
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Term
| What is the most common allergen? |
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Definition
House dust (all-year)
From dust mites (Dermatophagoides) |
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Term
| Describe fungal allergens |
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Definition
The mycelial fragments and spores of molds are common atopic allergens.
Indoor molds tend to cause perennial disease while outdoor molds cause seasonal disease. |
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Term
| How are atopic diseases tested? |
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Definition
Immediate sensitivity tests
Usually positive for the offending allergens |
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Term
| What is the difference between extrinsic and intrinsic asthma? |
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Definition
Exrinsic- allergic asthma, early in life
Intrinsic- usually adult, preceded by respiratory virus |
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Term
| Define aspirin intolerance |
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Definition
| An idiosyncratic reaction to aspirin and other NSAIDs that occurs in perhaps 10% of asthmatics |
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Term
| Describe atopic dermatitis |
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Definition
aka atopic eczema
More common in children
Usually independent of allergens, may be a defect in T cells |
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Term
| Define allergic gastroenteropathy |
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Definition
Least common atopic disease
More common in children
Cow's milk most common allergen |
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Term
| List four ways non-atopic IgE-mediated reactions are different than atopic diseases |
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Definition
1. No genetic predisposition.
2. Patients do not have hyperresponsive shock tissues
3. Immunogens are ingestants and injectants
4. Manifestations of the allergy are different |
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Term
| Define anaphylactoid reactions |
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Definition
Similar to allergic reactions in manifestation but caused by non- immunologic mechanisms
Aggregates in Ig products may activate complement by alternative pathway |
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Term
| List some common allergens for non-atopic IgE-mediated disease |
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Definition
Foods (peanuts, shellfish, eggs)
Drugs (injectants, any drug)
Hymenoptera venom |
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Term
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Definition
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Term
| List three clinical manifestations of non-atopic IgE-mediated disease |
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Definition
1. Anaphylaxis
2. Uriticaria
3. Angioedema |
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Term
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Definition
| Systemic IgE-mediated reaction occurring in multiple organs |
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Term
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Definition
| Hives; cutaneous anaphylaxis |
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Term
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Definition
| More serious form of urticaria involving subcutaneous tissues |
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Term
| Define immune complex disease |
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Definition
Immune complexes of allergen with IgG (or IgM) activate complement giving rise to anaphylatoxin and chemotactic activities.
This acute inflammation with neutrophil infiltration typically occurs in small vessels and vasculitis is the prototype lesion. |
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Term
| List the two main syndromes of immune complex disease |
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Definition
1. Arthus reaction (in skin)
2. Serum sickness |
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Term
| Describe the typical allergen in immune complex disease |
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Definition
| Usually classical protein immunogens rather than haptens |
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Term
| List three examples of allergens in immune complex disease |
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Definition
1. Tetanus toxoid (causes Arthus)
2. Equine antisera (serum sickness)
3. Haptens (serum sickness) |
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Term
| What sort of allergen dose dose is required for immune complex disease? |
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Definition
Optimum absolute and relative amounts of antibody and antigen
Not too much antibody, about equal amounts to lead to crosslinking |
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Term
| Do immune complex diseases have a genetic basis? |
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Definition
| Yes, certain people are predisposed because of deficiencies in the normal mechanisms which clear immune complexes |
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Term
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Definition
| Immune complex disease: may range from relatively mild maculopapular rashes to the classic hemorrhagic necrosis (more in animals) |
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Term
| Describe the timepath of an Arthus reaction |
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Definition
Typically follow administration of a complete antigen to an immunized individual (e.g., booster doses of vaccines, allergy immunotherapy, and other protein drugs).
Usually appear within several hours of administration and resolve within several days |
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Term
| Define primary serum sickness |
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Definition
An immune complex disease
Primary serum sickness typically occurs about a week (4-21 days) following administration of a complete, foreign immunogen like an equine antisera and the reaction usually resolves within 1-4 weeks. |
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Term
| List symptoms of serum sickness |
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Definition
| Symptoms include rash, swelling and pain at site of injection along with fever, headache, nausea, vomiting, malaise, arthralgia, and myalgia. |
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Term
| Define serum sickness syndrome |
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Definition
| Serum sickness syndrome caused by haptens has similar characteristics but is generally much milder than serum sickness |
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Term
| List autoimmune diseases caused by immune complex disease |
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Definition
| Rheumatoid arthritis, lupus, and may include other autoimmune disorders. |
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Term
| Define Extrinsic Allergic Alveolitis (Hypersensitivity Pneumonitis) |
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Definition
| Allergic pulmonary reactions to various organic dusts that was formerly thought to be an immune complex reaction (now thought to be cell-mediateD) |
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Term
| Define Allergic Bronchopulmonary Aspergillosis |
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Definition
A hypersensitivity response to the fungus Aspergillus, causing bronchospasms and airway inflammation
Multiple mechanisms: IgE-mediated, immune complex, and/or perhaps cell-mediated |
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Term
| What is the most common type of cell-mediated allergy? |
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Definition
| Allergic contact dermatitis |
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Term
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Definition
Poison ivy, poison oak, and poison sumac
Very common and an excellent prototype for allergic contact dermatitis. |
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Term
| Give two examples of a delayed hypersensitivity test |
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Definition
patch test for allergic contact dermatitis
tuberculin test for tuberculosis |
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Term
| List four pathologies that result from cell-mediated allergy |
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Definition
1. Allograft rejection
2. Viral tissue destruction
3. Autoimmune disease destruction(ex. MS)
4. Adverse drug reactions |
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Term
| Describe the allergens for allergic contact dermatitis |
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Definition
Usually small, lipid-soluble, haptens
(However, nickel isn't lipophillic) |
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Term
| Define Extrinsic Allergic Alveolitis |
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Definition
| An occupational illness caused by organic dusts and cell-mediated allergy |
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Term
| List four ways to diagnose a drug allergy |
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Definition
1. Comprehensive history
2. Sensitivity testing
3. In vitro tests
4. Provocation (challenge) testing |
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Term
How much of the population is allergic to penicillin?
How much of the population has anti-penicillin IgG? |
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Definition
| Penicillin allergy occurs in only 2-3% of patients, but 100% have IgG against it |
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Term
| What form of penicillin causes 75% of the reactions? |
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Definition
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Term
| What drug is used to test for a penicillin allergy? |
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Definition
| BENZYLPENICILLOYL POLYLYSINE (Pre-Pen, Hollister-Stier) |
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Term
| Why did insulin previously cause allergy? |
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Definition
Insulin is a reasonably good model for peptide drugs.
It is small enough not to be highly immunogenic but the dosage and regimen provides adequate opportunity for sensitization.
It was formerly available from multiple sources which differ slightly—bovine, porcine, human. |
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Term
| Is insulin allergy still a problem? |
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Definition
| No, because we don't use bovine or porcine insulin anymore |
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