SJS Flashcards
What is Stevens-Johnson Syndrome (SJS)?
A rare, severe, and potentially life-threatening hypersensitivity reaction characterized by extensive epidermal necrosis and mucocutaneous involvement.
How is SJS related to toxic epidermal necrolysis (TEN)?
SJS and TEN are part of the same spectrum of disorders; the distinction is based on the extent of body surface area (BSA) involvement:
SJS: <10% BSA.
SJS/TEN overlap: 10–30% BSA.
TEN: >30% BSA.
What are the most common causes of SJS?
Medications (most common):
- Anticonvulsants (e.g., carbamazepine, lamotrigine, phenytoin).
- Sulfonamides and other antibiotics (e.g., trimethoprim-sulfamethoxazole).
- NSAIDs.
- Allopurinol.
Infections: Mycoplasma pneumoniae, herpes simplex virus.
Idiopathic: In some cases, no clear cause is identified.
What is the underlying mechanism of SJS?
A hypersensitivity reaction mediated by cytotoxic T-cells and natural killer cells, leading to widespread keratinocyte apoptosis and epidermal necrosis.
What role does the HLA genotype play in SJS?
Certain HLA alleles (e.g., HLA-B*1502) predispose individuals to drug-induced SJS, particularly with carbamazepine.
What are the hallmark symptoms of SJS?
Prodromal phase: Fever, malaise, cough, and sore throat, resembling an upper respiratory infection.
Skin lesions: Painful, erythematous macules that evolve into blisters and sloughing of the epidermis.
Mucosal involvement: Painful erosions in the oral cavity, eyes, and genitals.
What is Nikolsky’s sign in SJS?
Gentle pressure on affected skin causes the epidermis to shear off, indicating severe skin fragility.
Which mucous membranes are commonly affected in SJS?
Oral cavity, eyes (conjunctiva), genitals, and respiratory tract.
What are key histopathological features of SJS?
Keratinocyte apoptosis.
Subepidermal blistering.
Sparse lymphocytic infiltrate.
What is the cornerstone of SJS management?
Early recognition, prompt withdrawal of the offending agent, and supportive care.
What supportive care is essential in SJS?
Fluid and electrolyte replacement.
Wound care similar to burn management.
Pain management.
Nutritional support.
Prevention and treatment of secondary infections.
Are systemic corticosteroids used in SJS?
The use of corticosteroids is controversial and may be considered in the early stages of SJS under close monitoring.
What immunomodulatory therapies are used in severe cases of SJS?
Intravenous immunoglobulin (IVIG): Blocks Fas-mediated keratinocyte apoptosis.
Cyclosporine: Inhibits T-cell activation.
Biologics (e.g., TNF-α inhibitors like etanercept): Emerging as potential treatments.
How should eye involvement in SJS be managed?
Immediate ophthalmologic consultation, use of lubricants, corticosteroid drops, or amniotic membrane grafting in severe cases.
