Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at LSU (Shreveport) Department of Allergy and Immunology
When drug reactions resembling allergy happen, they are called drug hypersensitivity reactions (DHRs). Drug hypersensitivity reactions may be allergic or nonallergic. Drug allergies are drug hypersensitivity reactions caused by the immune system.
T cell-meditated drug hypersensitivity subclassified as types IVabcd
IVa - 1 = Th1
IVb - 2 = Th2
IVc = cytotoxic CD8 T cells
IVd
Diagnosis of drug allergy
HASTA la vista (Spanish, See you later)
History
Assemble a list of drugs and rank them
Stop all drug candidates
Test
Administer - dose escalation or desensitization
Classification of adverse reactions to drugs: SOAP III
Side effect
Overdose
Allergy
Pseudoallergy
Interaction
Intolerance
Idiosyncrasy
Classification of adverse reactions to drugs: "SOAP III" mnemonic (click to enlarge the image).
Rule of 10s in ADR
10% of patients develop ADR
10% of these are due to allergy
10% of these lead to anaphylaxis
10 % of these lead to death
Mnemonics for penicillin allergy skin testing
Major penicillin determinant test detects
Majority of patients with penicillin allergy
Minor determinant test
Minorizes the risk
Manifestations of beta-lactams hypersensitivity: MAUS
Maculopapular exanthema, 19%
Anaphylaxis without shock, 19%
Urticaria, 36%
Shock, anaphylactic shock, 17%
References: Clinical presentation and time course in hypersensitivity reactions to β-lactams. Allergy, 2007.
Samter's triad include asthma, aspirin sensitivity, and nasal/ethmoidal polyposis:
ASPirin
Asthma
Sensitivity to aspirin
Polyps
T
Toxic epidermal necrosis (TEN)
Thirty percent of the skin (SJS less than 10%)
"Terrible" prognosis
Management of adverse drug reactions: PAD
Premedication with antihistamines and steroids
Avoidance
Desensitization
Published: 10/01/2009
Updated: 03/01/2014
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