Drug Eruptions Flashcards
what are the 2 types of drug eruptions?
allergic (non-dose dependent) and non-allergic (dose dependent)
morphologies of drug reactions
exanthematous- pigmentation
urticarial- itch/pain
papulosquamous- photosensitivity
characteristic presentation
new medication with symmetrical skin eruption
ix and mx for drug eruptions
hx and exam, patch test, biopsy
mx- stop meds, topical steroids, antihistamines
epi of exanthematous drug reaction (EDR)
most common, 4-21 days after drug onset
pathophysiology of Exanthematous Drug eruption.
t-cell mediated type 4 HS reaction
aetiology of EDR
penicillin, sulphonamides, erythromycin, streptomycin, allopurinol, anti-epileptics, NSAIDs
s/s of EDR
widespread symmetrical morbilliform rash, pruritus, mild fever. starts in torso and spreads to limbs and face.
severe cases- mucosal membranes, face-facial erythema and oedema
mx of EDR
self-limiting (1-2 weeks)
which 2 drug types cause an IgE mediates T1 HS reaction and what is this drug reaction called
urticarial drug reaction
- b-lactam abx
- direct mass cell degranulation (NSAIDs, opiates, aspirin)
acneiform skin reaction are caused by…
steroids
ACEI, penicillin and furosemide may cause…
bullous disease
what is a fixed drug reaction
patches that occur at same site each time drug is taken
which drugs cause a fixed drug reaction
tetracyclines, paracetamol, NSAIDs, carbamezapine
s/s of fixed drug reactions
well demarcated, red painful lesions at hands, genitilia, lips
mx of fixed drug reactions
self resolves with hyper pigmentation
what are 4 severe cutaneous drug reactions?
stevens johnson syndrome
drug reaction with eosinophilia & systemic symptoms (DRESS)
acute generalised exanthematous pustulosis
phototoxic drug reactions
what is Stevens Johnson syndrome and toxic epidermal necrolysis
severe mucocutaneous disorders that are potentially life threatening. characterised by varying extents of blistering/ eidermal detachment and mucosal ulceration
initial symptoms of Stevens Johnson
malaise, fever, tender areas of maculopapular erythema on torso with inflammation of mucosa
characteristic symptoms of Stevens Johnson that differ from toxic epidermal necrolysis
SJS: hands and feet
TEN: widespread flaccid blisters form with skin that wrinkles on gentle pressure (Nikolosky’s)
what is ‘skin that wrinkles on gentle pressure’ called
Nikolosky’s sign
tx of SJS/TEN?
high dose steroids, cyclosporin and IV IGs
what score is given for prognosis of SJS/TEN?
SCORTEN system
morbidity of SJS/TEN?
systemic issues- renal impairment, hypotension, sepsis, multi organ failure
what is DRESS?
2-6 weeks after drug exposure and results in widespread erythema, facial oedema, fever, lymphadenopathy, hepatosplenomegaly
ix findings for DRESS
inc eosinophilia and inc hepatic transferases
mx for DRESS
oral steroids for 3 months
prognosis of DRESS
mortality is 10%
acute generalised exanthematous pustulosis (AGEP) aetiology?
ca channel blockers, some abs
s/s of AGEP?
exanthem with numerous small non follicular sterile papules around neck, axilla and groin
AGEP resolution?
with peeling
main drugs that cause phototoxic drug reactions
doxycycline, amiodarone, quinine, chlorpromazine
s/s of PDRs?
immediate prickling with delayed erythema & pigmentation, exaggerated sunburn, skin fragility
