3.1.2 Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis Flashcards
Name this dz: Target like lesions, <10% of the body affected; Commonly triggered by HSV or mycoplasma
Erythema multiforme
What make Erythroderma and Erythematous Drug Eruptions different from SJS/TEN?
Lacks mucosal involvement
What is a phototoxic eruption?
Reaction to recent sun exposure, drug induced
What are the two key aspects of SJS/TEN?
Severe mucocutaneous reactions
Triggered by medications (started 4-8wks prior)
The SJS/TEN share the same etiology. They only differ based on their severity. Describe when it would be SJS, SJS/TEN overlap, or just TEN?
Severity based on body surface area affected.
SJS: <10% affected
SJS/TEN: overlap 10-30% affected
TEN: >30% is affected
Which is more prevalent SJS or TEN?
SJS, 3:1
What condition can increase one’s risk of SJS/TEN 100-fold?
HIV
What is the most common etiology of SJS/TEN? Give some examples.
Medications (1st 4-8 wks of taking the medication)
Allopurinol (treatment of gout), Anti-seizure (phenobarbital and carbamazepine), Antibacterial sulfonamides (TMP-SMX – Bactrim), Lamotrigine (bipolar disease/seizures - Lamictal), Nevirapine (non-nucleoside reverse transcriptase inhibitor – used in the treatment of HIV), Oxicam NSAIDs
What are some infections associated with SJS/TEN?
Mycoplasma pneumonia, Cytomegalovirus, Epstein-Barr virus, Mycobacteria, Diphtheria
What are the two genes that associated w/ an increased risk of SJS/TEN? What is the appropriate course of action when considering a patient’s risk of developing SJS/TEN?
HLA-B*1502 (Carbamazepine, phenytoin, phenobarbital) and HLA-B*5801 (Allopurinol)
- Consider screening these patients prior to starting the medication
- Do not start these medications if patient is a known carrier of one of these mutations
What are some genetic polymorphisms associated with SJS/TEN?
CYP2C19 – coding for cytochrome p450– reduced clearance of medications in the liver and increased risk of severe cutaneous reactions
IL-4R gene
Prostaglandin E receptor 3 gene
High levels of which granzyme have been associated with increased severity of SJS/TEN?
Granzyme B
What is granulysin?
Antimicrobial and cytotoxic, Expressed by cytotoxic T cells and NK cells, Causes release of caspase 3, Keratinocyte death, Found in blister fluid of lesions
Describe the histopathologic nature of the necrosis found in SJS/TEN.
Partial to full-thickness necrosis of the epidermis
What is the term for the 1-3 days prior to the onset of skin lesions. During this time patients may experience:
§Fever (often >39°C – 102.2°F)
§Flu-like symptoms – malaise, myalgia, arthralgia
§Photophobia (light bothers the eyes)
§Conjunctival itching/burning
§Dysphagia (painful swallowing)
§Exanthematous eruption (red rash)
Prodrome
What does this patient have?
DSLs…
Jk, SJS/TEN
