Y5 - Drug reactions (incl. Stevens-Johnson syndrome, toxic epidermal necrolysis spectrum) Flashcards
def of SJS
severe skin detachment with mucocutaneous complications
what is SJS a more severe version of
erythema multiforme major
what is SJS a less severe version of
toxic epidermal necrolysis (TEN)
how is SJS and TEN differentiated
SJS <10% total body surface area
TEN <30% total body surface area
what is Nikolskys sign?
when the epidermal layer easily sloughs off when pressure is applied
epi
TEN rare than SJS
aetiology
1 infection
2 vaccination
3 medicine
what infections cause SJS
URTIs Pharyngitis Herpes EBV Mycoplasma pneumoniae
what vaccinations cause SJS
smallpox vaccination
what medicines cause SJS
anticonvulsants
antibiotics
antifungals
corticosteroids
pathophysiology
detachment of epidermis from the papillary dermis at the epidermal-dermal junction
signs and symptoms
RFs
sudden rash which develops after a new medicine
mucosal involvement
-erosions or ulceration of eyes. lips, mouth, eye, genital area
nikolskys sign
who is mucosal involvement more common in
SJS patients
RFs
anticonvulsants (carbamazepine, phenobarbital, phenytoin)
recent infection (mycoplasma pneumoniae)
recent antibiotic use
SLE
what is the definitive test for diagnosis
skin biopsy
what would you find on skin biopsy
keratinocyte apoptosis with detachment of the epidermal layer of the skin from the dermal layer
how would you rule out toxic shock syndrome
with blood cultures positive for staph or strep
negative in SJS/TEN
what would eosinophilia on FBC suggest
hypersensitivity syndrome
management
1 urgent evaluation and withdrawal of causative agent
2 dressings, topical antibacterials, emollients
-bacitracin topical
-silver sulfadiazine
3 opthalmological examination
4 IV fluids and nutritional support
complications
dehydration is common
compartment syndrome
abnormal skin pigmentation
prognosis
prognosis is best when:
- patient <50yrs
- total body surface area is low
- patients are transferred to a burn centre
- no sepsis
- do not require anitbiotics
what is the mortality in SJS
1-5%
what is the mortality in TEN
25-35%
