Allergic Reacitions Flashcards
Which type of allergic reaction is mediated by IgE?
Type I
Which type of allergic reaction is mediated by IgM or IgG?
Type II, cytotoxic
Which type of allergic reaction is mediated by Ab-Ag complexes?
Type III
Which type of allergic reaction is mediated by T-cells?
Type IV
True or False: The severity of acute phase reaction in Type I hypersensitivity is a predictor of severity of the last phase.
True, since more cytokines get released, leading to more baso and eos activation.
Goodpastures and Myesthenia gravis are examples of which type of hypersensitivity reaction?
Type II
Leukoclastic vasculitis is a generic term associated with which type of hypersensitivity?
Type III
In general, what is the difference between the way serum sickness and Arthus reaction are triggered.
In serum sickness, un-immunized host gets a large amount of Ag. In Arthus reaction, hyper-immunized host gets Ag injection.
Serum sickness is an example of which type of hypersenitivity?
Type III
Hymenoptera stings can cause Type 1 as well as this other type of hypersensitivity.
Type III leading to serum sickness.
What is the description of the rash commonly associated with serum sickness?
Serpiginous rash of hands and feet.
What is the Arthus reaction?
A local reaction at the site of innoculation, caused by Type III hypersensitivity. The host is hyper-immunized to the offending Ag.
Nickel allergy is classically what type of hypersensitivity? Name another common example of this type.
Type IV. The tuberculin reaction is also type IV.
Graves is similar to Goodpastures and Myesthenia Gravis in that it is caused by a hypersensitivity reaction, but it isn’t grouped with them. Why? What type of reaction are they? What type of reaction is Graves?
They are Type II and are different because Graves (Type V) is a disease that is caused because of ACTIVATION by the Ab-Ag complex. In type II, there is cytotoxic destruction because tissue gets inappropriately tagged with Ab.
Urogenital malformations are associated with allergy to what substance?
Latex
Which complement molecules are anaphylactoid?
C3a, C4a, C5a
Which substances are associated with anaphylactoid reactions?
Aspirin, NSAIDs, contrast, sulfites
How is anaphylaxis and anaphylactoid the same? Different?
Both involve mast cell degranulation. However, anaphylactoid is NOT IgE mediated.
What is the treatment of anaphylactic and anaphylactoid reactions?
Epinephrine! 0.01 mg/kg 1:1000 concentration.
What would you do if you had a patient on beta blockers who was given epinephrine for anaphylaxis and had a blunted response?
Give second-line agents like glucagon and vasopressin. The point is that you would still have epi as first line therapy.
What are some differences in acute vs. chronic urticaria (in terms of duration of symptoms, triggers?)
Acute urticaria are generally IgE mediated and triggers are typical allergies. Chronic last 4-6 weeks, 90% idiopathic, and causes including thyroid, autoimmune, malignancy and chronic infection.
A 13 year old girl is seen in your office with punctate hives that are very pruritic. They come and go. What HPI questions would help you sort out the cause?
Does this just occur with showering? Heat triggers cholinergic urticaria, described like this vignette.
There is one type of urticaria that is not benign and often gets missed. Which is it? What are some red flags associated with this condition?
Urticarial vasculitis. Red flags:
- Lesions > 24 hours
- Lesions that are fixed location.
Residual ecchymosis, hyperpigment, or purpura. - Non-pruritic, tender, burning
- Arthritis, fever, fatigue
What are some diagnostic features in urticarial vasculitis?
Skin bx diagnosis it but C3/C4 will usually be low and there may be antibodies to C1q.
