Stevens Johnson Syndrome (SJS)

Stevens–Johnson Syndrome (SJS) is a rare but serious acute mucocutaneous hypersensitivity reaction, most commonly triggered by medications. It is characterized by epidermal necrosis leading to blistering and detachment of the skin and mucous membranes.

SJS represents the milder end of the SJS/TEN spectrum:

• SJS: <10% body surface area detachment

• SJS/TEN overlap: 10–30%

• TEN: >30%

This condition is a medical emergency due to risk of dehydration, sepsis, and organ failure.

Etiology

Drug-induced (most common)

• Sulfonamides

• Anticonvulsants (carbamazepine, phenytoin, phenobarbital, lamotrigine)

• Allopurinol

• Nevirapine

• NSAIDs (oxicam group)

• Penicillins and cephalosporins

Infectious triggers (more common in children)

• Mycoplasma pneumoniae

• Viral infections (HSV, HIV)

Pathophysiology

Immune-mediated cytotoxic reaction:

• Drug antigen activates cytotoxic T-cells

• Keratinocyte apoptosis occurs

• Epidermis separates from dermis

• Leads to blistering and erosions of skin and mucosa

Risk Factors

• HIV infection

• Previous drug reactions

• Polypharmacy

• Genetic susceptibility (HLA-related)

• Malignancy

• Autoimmune disease

Signs and Symptoms

Prodromal phase (1–3 days)

• Fever

• Malaise

• Arthralgia

• Sore throat

• Burning eyes

Cutaneous findings

• Abrupt erythema multiform-like rash

• Target lesions evolving to blisters

• Skin tenderness

• Peeling epidermis

Mucosal involvement

Oral

• Painful erosions

• Hemorrhagic crusted lips

• Necrotic white pseudomembrane

Ocular (70–90%)

• Erosive conjunctivitis

• Photophobia

• Risk of corneal scarring

Genital (60–70%)

• Painful erosions

• Dysuria

Diagnostic Criteria

Clinical diagnosis based on:

• Sudden erythema multiform-like rash

• Prodrome with fever, malaise, arthralgia

• Hemorrhagic crusted lips and oral erosions

• Eye involvement (erosive conjunctivitis)

• Genital mucosal erosions

• Skin detachment <10% BSA

Investigations

Laboratory tests

• Full blood count

• Urea and electrolytes

• Liver function tests

• Blood glucose

• CRP

Infection assessment

• Blood cultures if febrile

• Swabs from erosions

Confirmatory test

• Skin biopsy → epidermal necrosis

Treatment

Admission and Monitoring

• Immediate hospital admission

• Close monitoring of fluids and electrolytes

• Nutritional support

• Temperature regulation

Non-Pharmacological Treatment

• Stop suspected drug immediately

• Maintain hydration

• Gentle wound care (non-adhesive dressings)

• Oral care with saline rinses

• Eye lubrication and ophthalmology review

• Prevent secondary infection

• Pain control

Pharmacological Treatment

• Early systemic corticosteroids (short course, early stage only)

• Topical antiseptic dressings

• Treat secondary infections promptly with antibiotics

• IV fluids for dehydration

Late corticosteroid use increases infection risk and delays healing

Complications

Acute

• Dehydration

• Sepsis

• Electrolyte imbalance

• Pneumonia

Long-term

• Ocular scarring → blindness

• Genital adhesions

• Chronic dry eyes

• Skin pigmentation changes

Prevention

• Avoid re-exposure to culprit drug

• Record allergy in medical file

• Patient drug-alert card

• Careful prescribing in HIV patients

• Pharmacovigilance reporting