Drug Reactions Flashcards
Most common cutaneous drug reaction
Exanthematic eruption
5 features of exanthematic eruption
Itchy Widespread Symmetrical Erythematous Maculopapular
Onset of exanthematic eruption
Often 1-2 weeks
hours-days if sensitised
Most common causative drugs of exanthematic eruption
Abx: Aminopenicillins, Beta-lactams, sulfonamides, clindamycin, tetracyclines
Allopurinol
Anticonvulsants
Most common causative drugs of urticaria
Abx- Penicillins, Cephalosporins, Sulfonamides
Opiate analgesics- Morphine, Codeine
NSAIDs
ACE inhibitors
5 features of urticarial drug reaction
Intensely itchy Circumscribed Raised Erythematous, often with central pallor Rapid onset
2 associations of urticarial drug reaction
Angioedema
Anaphylaxis
3 features of angioedema
swelling of the deeper dermis and subcutaneous tissues
Disfiguring if involves face + lips
Life threatening if airway obstruction occurs from laryngeal edema/ tongue swelling.
3 mechanisms of urticarial drug reaction
Immune/ IgE mediated: Penicillins/ Cephalosporins
Mast cell activation: Morphine, Codeine, NSAIDs
Bradykinin accumulation: ACE inhibitors
Immunoallergic reactions
I: IgE, urticaria, angioedema, anaphylaxis
II: immune-complex mediated, vasculitis, thrombocyticopenic purpura
III: lymphocytic, maculopapular exanthema, photosensitivity
IV: Contact dermatitis, EM-SJS-TEN spectrum
6 features of lichenoid drug eruption
Planar Papular Pruritic Purple Polished Polygonal/ pigmented
Most common causative drugs of Lichenoid drug eruption
Beta-blockers ACE inhibitors Methyldopa Penicillamine Quinidine Antimalarials Thiazide diuretics
2 features of exfoliative dermatitis/ erythroderma
diffuse erythema + scaling involving ≥90 percent of body surface area
Systemically unwell with lymphadenopathy + malaise
Most common causative drugs of exfoliative dermatitis/ erythroderma
Allopurinol ACE inhibitors Abx: Penicillins, Sulfonamides Anticonvulsants: Carbamazepine, Phenytoin Barbiturates
Tx for exanthematic eruption
Drug withdrawal
Topical potent corticosteroid
Oral antihistamine
Tx for urticaria
Antihistamines- Loratadine Prednisolone PO (severe)
Tx for angioedema
Antihistamines + Prednisolone PO (non-anaphylactic)
Adrenaline IM + O2 + Fluids (anaphylactic)
Tx for exfoliative dermatitis/ erythroderma
Emolients + wet wraps Topical steroids (mild) Oral steroids (severe)
Tx for exfoliative dermatitis/ erythroderma
Emollients + wet wraps Topical steroids (mild) Oral steroids (severe)
Most common causative drugs of SJS/ TEN
Sulfonamides
Allopurinol
NSAIDs
Anti-convulsants
Difference between SJS and TEN
SJS: Detachment affects < 10% of body surface
TEN: >30%
What is DRESS?
Drug reaction with eosinophilia + systemic symptoms
5 features of DRESS
Fever (38 to 40°C) Malaise Lymphadenopathy Skin eruption 2-6 weeks of starting drug
Most common causative drugs of DRESS
Antiepileptics: carbamazepine, phenytoin, lamotrigine, oxcarbazepine, + phenobarbital
Allopurinol
Sulfonamides
