Stevens-Johnson syndrome and TEN Flashcards
Male/female predominance and age predilection of SJS/TEN?
- F>M , elderly more frequently affected
What are some groups that are at increased risk of SJS/TEN?
- HLA-B 1502 (asians and east indians exposed to carbamazepine)
- HLA-B 3101 (europeans exposed to carbamazepine)
- HLA-B 5801 (Han Chinese esposed to allopurinol)
- AIDS patients (1000 fold increased risk)
Mechanism of SJS/TEN
Patient with predispotion exposed to drug/metabolites
1) Activation of FAS death receptor on keratinocytes
2. ) CD8 cells and NK cells release granulysin (major regulator of apoptosis), granzyme B, and perforin
3. ) granulysin, granzyme B, and perforin cause apoptosis of keratinocytes—-> necrosis and sloughing of skin and mucous membranes
Difference between SJS/TEN:
SJS/TEN exist on a spectrum (BSA: body surface area)
o SJS < 10% BSA
o TEN > 30% BSA
o SJS/TEN overlap syndrome: 10-30% BSA
How long after drug initiation does SJS/TEN occur? Exceptions to this time frame?
- 1-2 weeks
- exceptions
- can occur within a few days if patient has taken medication in the past
- anticonvulsants can take many weeks before symptoms occur
Most common medications w/ SJS/TEN
Sulfamethoxazole-Trimethoprim
▪ Allopurinol
▪ Phenytoin, Carbamazepine, Lamotrigine
▪ Penicillins, Cephalosporins, Carbapenems, Monobactams
▪ NSAIDs
▪ Abacavir, Nevirapine
Clinical presentation of SJS/TEN:
1) prodrome of fever and flu-like symtoms 1-2 weeks after initial medication
2) 1-3 days later mucocutaneous changes noted (Look for erythema or erosions of skin/mucous membranes)
- skin lesions start on trunk as erythematous macules and targetoid w/ dusky or purpuric center (remember EM has typical targetoid lesions that are raised and have three zones)
3) lesions will be tender to touch and quickly coalesce in hours to days
4) May progress to flaccid blisters and sheets of skin that start to desquamate
SJS/TEN will almost always be present in which locations that you should inspect??
- mucosal involvement:
- check eyes, nose, mouth, and genital mucosa
How to distinguish SJS/TEN from EM?
- EM likes to involve distal extremities which is much less common in SJS
- EM has typical, papular targetoid lesions, SJS/TEN are macular targets
Differential diagnosis for desquamating rashes?
TEST DRESS PPMG
- TEN/SJS
- EM major
- Staph scalded skin syndrome
- toxic- shock syndrome
- DRESS
- Purpura fulminans
- Pemphigus vulgaris
- Mycoplasma pneumonia-induced rash and mucositis (MIRM)
- Graft vs host disease (acute
SJS, TEN, EM Major, SSSS, toxic-shock syndrome, Mycoplasma pneumonia-induced rash and mucositis (MIRM), DRESS (DIHS), purpura fulminans, acute graft-versus-host dz, and pemphigus vulgaris
Histology of SJS/TEN:
Scattered apoptotic keratinocytes
- Unimpressive perivascular lymphohistiocytic infiltrate w/ eosinophils
- As lesions progress, there will be full thickness epidermal necrosis & development of subepidermal blisters
(arrow in pic is a dead red- apoptotic keratinocyte)
Two blistering physical exam signs in SJS/TEN:
1) Nikolsky sign: tangential pressure induces sloughing of skin
2) Asboe-Hansen sign: vertical pressure applied to top of bulla results in extension of blister onto adjacently, previously unaffected skin.
What is the prognostic scoring system for SJS/TEN? Whats the mnemonic to remember the criteria?
- Which of these is the most important risk factor for mortality?
SCORTEN:
Remember TAMEBUG:
- Tachycardia >120 BPM
- Age >40
- history of Malignancy Bicarb < 20 is most important predictor of mortality
- Epidermal loss >10%
- Bicarb level <20 meq/dl
- Urea (BUN) >27
- Glucose >250
When are the most important times to use the SCORTEN scoring system for SJS/TEN?
- day 1 and again on day 3
What are the most common sequelae of SJS/TEN?
- Ocular sequelae (up to 80%)
- chronic dry eyes, symblepharon (image shown), blindness
What is symblepharon and whats a common scenario you may see it?
- adhesions between the conjunctiva and cornea/adjacent conjunctiva
- seen as sequelae of SJS/TEN
