Drug Allergies Flashcards
What type of allergy is immediate in onset, delayed
Type 1/ type 2,3,4
Which allergic reaction is antibody mediated
Type 1
What are clinical features of Type 1 antibody reactions
Hives, itching, flusing, angioedema, hypotension, anaphylaxis
T/F: There is not a fever in type 1 allergy reactions
True
What is anaphylaxis, goals of therapy
acute, life-threatening allergic reaction involing multiple organ systems, anaphylactic shock
How often does Type 1 reactions causes problems for the skin, respiratory tract, GI, CV
80-90%, 70%, 40%, 35%
How quick is anaphylaxis
within 30 minutes of antigen exposure
T/F: Anigodema is only bilateral
False: Angioedema can be unilateral or bilateral
What type of angioedmea is a part of the type 1 allergic reaction
Mast-cell mediated
What are the criteria for having a type 1 allergic reaction
sudden skin or mucosal symptoms and signs, sudden respiratory symptoms and signs, sudden reduced BP or symptoms of end-organ dysfunction, sudden gastrointestinal symptoms
How many of the criteria is need to diagnose as a type 1 allergic reaction if the antigen is known, unkwown
2, 1
T/F; Skin manifestations must be present to be considered a type 1 allergic reaction
False: Skin manifestations is absent in 10 to 20% of the cases
Which allergic reaction is a cytotoxic reaction
Type 2
What causes a type 2 allergic reaction
Drug binds to surfaces of certain cell types and act as antigens
How long does it take for symptoms to occur in type 2 allergic reactions
1 week (can begin within hours if previously exposed)
What are clinical features of type 2 allergic reactions
hemolytic anemia, thrombocytopenia, leukopenia, neutropenia
What is heparin induced thrombocytopenia (HIT)
antibody initiates profound activation of platelets while, at the same time, initaiting their clearance by macrophages
What is a risk of HIT
low platelet count, blood clotting
Which allergic reaction is a immune-complex reaction
Type 3
What causes a type 3 allergic reaction
Free IgG or IgM binds to the drug to form free, soluble, circulating immune complexes that can percipitate into tissue causing an inflammatory response
When would Type 3 allergic reactions take place
after high dose, long term, or recurrent drug exposure
How long does it take for a type 3 allergic reaction to take place
1 week or more
What are the clinical features of type 3 drug allergies
Drug fever, vasculitits, serum sickness
What are differences between drug fever and infectious fever
fever will stop upon discontinuation of drug and recur within hours of re-challenge, commonly high: 102-104, patients often do not realize they have a fever
What cell type is usually present in only drug fever
Eosinophils
Which allergic reaction is cell mediated/delayed
Type 4
When do type 4 reactions take place
1-3 weeks
What are dangerous diseases that can occur due to type 4 allergic reactions
Stevens-Johnsons syndrome and Toxic Epidermal Necrolysis
What are indications of SJS and TENS, which is more dangerous
blistering and skin sloughing, TENS
What is Drug Rash with Eosinophilia and Systemic Symptoms
severe drug reaction that involves widespread rash, fever, and single or multi organ failure
What are organs affected by DRESS
Liver (80%), kidney, heart, lungs, muscle, pancreas
T/F: DRESS has the unique feature of single or multi organ failure and not all cases are associated with eosinophilia
True
When does aminopenicillin reaction occur
7 to 14 days after starting antibiotics
What is common in lupus but not drug induced lupus
malar rash and discoid lesions, renal involvement, positive double stranded DNA antibodies
T/F: A patient with positive anti-ds DNA and positive anti-histone antibodies likely has DILE
False: A patient with negative anti-dsDNA and postive anti-Histone antibodies likely has DILE
What drugs cause DILE
slufas, hydralizine, isoniazaid, procainamide, phenytoin
What are drugs that are started to be indicated for interstitial nephritis
PPIs
Which drugs cause drug induced phototoxicity/photoallergy
tetracyclines, sulfonamides, voriconazole, amiodarone
What is the most common cause of allergic drug reactions
Beta lactams
T/F: Skin testing for an antibiotic test not the drugbut instead the metabolite
True
What drug has cross reactivity to beta lactams
cephalosporins, carbapenam
What type of aztreonam could have cross reactivity with beta-lactams
ceftazidime (identical side chain to that aztreonam)
What is the drug that causes the 2nd most drug allergies, what part causes this
sulfonamides, arylamine side chain
T/F: Beta lactams are the most common causes for SJS and TEN
False: Sulfonamide allergy is the most common cause of Steven-Johnson Syndrome and Toxic Epidermal Necrosis
What causes Samter’s triad symptoms and cause type 1 reaction
Aspirin
What are the sympotms of Samter’s triad
hypersensitivity reaction, ashtma exacerbations, and nasal polyps
What drugs require HLA testing
Abacavir (all), carbamezapine, allopurinol, phenytoin
What drugs can treat the symptoms of urticaria
H1 antihistamines, H2 antihistamines and glucoroticoids (severe or progressing)
How is anaphylaxis treated
D/C suspected drug/antigen, IM injection of epinephrine, maintain 02 saturation over 92, lay patient down but keep legs raised, 0.9NaCl
Wha drugs treat breathing problems
albuterol, Ipratropium
How should corticosteroids be used in an allergic reaction
to prevent or minimize late phase reaction
how much epinephrine should be given in anaphylaxis, refractory anaphylaxis
.3mg, 1-4 mcg