Cutaneous drug eruptions Flashcards
what is a cutaneous drug eruption
any adverse reaction to a drug visible on the skin
are they common/uncommon
common - occur in 3% of hospital patients
can be allergic or non-allergic, give examples of both
allergic/immune mediated/hypersensitivity reaction
type I-IV
non allergic/non immune mediated
eg eczema, phototoxicity, psoriasis, pigmentation
are allergic cutaneous drug reactions dose dependant
no
are non allergic cutaneous drug eruptions dose dependant
yes
general presentation
dependant on type of reaction!!! type I - urticaria (5%) type II - pemphigus, pemphigoid type III - rash, purpura type IV - rash, erythema (95%)
Sudden onset symmetric skin eruptions
non allergic/non immune mediated
eg photosensitivity, pain, itch, pigmentation, psoriasis, skin erosion
type IV drug hypersensitivity presentation (95% of hypersensitivity reactions)
what is the onset
what is the presentation of a severe reaction
RASH!
can be exanthematous (rash) or morbilliform (measles like rash) or macorpapular (rash with small bumps)
onset 4-21 days
severe if - fever, blisters, SOB, involvement of face/mucous membrane
aetiology of type IV drug hypersensitivity (95% of hypersensitivity reactions)
antibiotics - penicillin, sulphonamide, erythromycin, streptomycin NSAIDs anti-epileptics phenytoin allopurinol
type I drug hypersensitivity presentation (5% of hypersensitivity reactions)
URTICARIA!
aetiology of type I drug hypersensitivity (5% of hypersensitivity reactions)
antibiotics - beta lactam, vancomycin, quinolones
NSAIDs
aspirin
opiates
type II drug hypersensitivity presentation
rash and itchy blisters (PHEMPHIGUS/PEMPHIGOID)
aetiology of type II drug hypersensitivity
ACE inhibitors
penicillin
furosemide
presentation of a fixed drug reaction
location - at site of drug administration only (eg hands, lips, genitalia but NOT in mucosa eg vagina, mouth)
red
painful
how does a fixed drug reaction resolve
with persistant pigmentation after removal of drug
what is phototoxic cutaneous drug reactions
photosensitivity to sunlight caused by drugs
aetiology of phototoxic cutaneous drug reactions
amiodarone, CA channel clockers, antibiotics, NSAIDs, BRAF inhibitors, immunosuppressants, thiazide diuretics
presentation of phototoxic cutaneous drug reactions
heat prickling
exaggerated sunburn
increased skin fragility
all in response to UVA/visible light
what are the investigations conducted if a cutaneous drug eruption is suspected
history and examination usually suffice phototesting patch test (if type IV suspected) skin prick (if type I suspected) NOT skin testing
general treatment of cutaneous drug reactions
removal of drug find alternative drug antihistamines topical steroids REPORT via yellow card scheme
complications of cutaneous drug reactions (if untreated)
steven Johnson syndrome (SJS)
toxic epidermal necrolysis (TEN)
drug reaction with eosinophilia and systemic symptoms (DRESS)
acute generalised exanthematous pustulosis (AGEP)
how does steven Johnson syndrome (SJS - a complication of cutaneous drug reaction) present (7)
flu like symptoms
fever
blistering, peeling (like TEN but <10% of skin)
eye problems - conjunctivitis, occlusion of lacrimal glands, corneal ulcer
what does TEN (a complication of cutaneous drug reaction) stand for
how does TEN present
toxic epidermal skin necrolysis
SKIN FAILURE
flu like symptoms, mouth erosions, generalised erythema, fever, blistering, peeling (like SJS but >30% of skin)
what are the complication of TEN
sepsis
organ failure
pneumonia
what is the prognosis of TEN
50% survival
what does DRESS (a complication of cutaneous drug reaction) stand for
how does DRESS present
drug reaction with eosinophilia and systemic symptoms
inflammation, rash, fever, lymphadenopathy
what does AGEP (a complication of cutaneous drug reaction) stand for
how does AGEP present
acute generalised exanthematous pustulosis
pustular rash
can be life threatening
what causes pityriasis rosea
viral infection
how does pityriasis rosea present
herald patch - single red and scaly area
then pink whole body rash
how is pityriasis rosea treated
self limiting, goes after 3 months
which skin infection is a ‘herald patch’ associated with
pityriasis rosea
