What are the clinical features of Stevens-Johnson syndrome?

Clinical Features of Stevens-Johnson Syndrome

Stevens-Johnson Syndrome (SJS) is characterized by widespread epidermal necrolysis with mucosal involvement, typically presenting with a prodromal illness followed by painful skin lesions and multi-site mucositis. 1

Prodromal Phase

• Fever, malaise, and upper respiratory tract symptoms typically precede the eruption by several days 1
• This prodromal phase can be difficult to distinguish from a precipitating infection 1
• "Influenza-like" symptoms including anorexia typically occur 4-28 days after exposure to a causative drug 2

Cutaneous Manifestations

• Early features:

  • Cutaneous pain is a prominent early warning sign that should alert clinicians to incipient epidermal necrolysis 1
  • Initial lesions are atypical targets and/or purpuric macules 1
  • Typically begins on upper torso, proximal limbs, and face before spreading to the rest of the body 1
  • Palms and soles involvement is often prominent 1

• Progressive features:

  • Large areas of confluent erythema develop in severe cases 1
  • Positive Nikolsky sign (epidermis peels away with gentle lateral pressure) 1
  • Flaccid blisters form as necrotic epidermis separates from underlying dermis 1
  • Extensive necrolysis results in detachment of epidermal sheets exposing denuded dermis 1
  • Exposed dermis exudes serum, bleeds easily, and is prone to secondary infection 1

Mucosal Involvement

• Mucous membrane involvement of eyes, mouth, nose, and genitalia is usually an early feature 1
• Results in erosive and hemorrhagic mucositis 1
• Ocular inflammation may develop before skin signs appear 1
• Early eye involvement presents as purulent keratoconjunctivitis with eyelid edema 1

Disease Classification

SJS/TEN is classified based on the percentage of body surface area (BSA) with epidermal detachment:

• SJS: <10% BSA involvement
• SJS/TEN overlap: 10-30% BSA involvement
• TEN: >30% BSA involvement 3, 4

Histopathological Features

• Variable epidermal damage ranging from individual cell apoptosis to confluent epidermal necrosis
• Basal cell vacuolar degeneration
• Subepidermal vesicle or bulla formation
• Mild perivascular infiltrate of lymphocytes and histiocytes in the dermis
• Small numbers of eosinophils may be present 1

Systemic Involvement

• Respiratory tract: cough, dyspnea, bronchial hypersecretion, and hemoptysis 1
• Gastrointestinal tract: diarrhea and abdominal distension 1
• Septicemia is a leading cause of morbidity and mortality in the acute phase 4
• Pulmonary and hepatic involvement is common 4

Diagnostic Considerations

• Diagnosis is based on clinical presentation and confirmed with skin biopsy 1
• Differential diagnosis includes:
  • Erythema multiforme major (EMM)
  • Pemphigus vulgaris
  • Bullous pemphigoid
  • Staphylococcal scalded skin syndrome (SSSS)
  • Other immunobullous disorders 1

Etiology

• Predominantly drug-induced (anticonvulsants, antibiotics, NSAIDs, allopurinol) 4
• Can be triggered by infections, particularly in children (Herpes Simplex Virus, Mycoplasma pneumoniae) 3
• Mycoplasma-induced SJS may present with predominantly mucous membrane involvement and minimal cutaneous lesions 1

Complications and Sequelae

Long-term complications include:

• Skin pigmentation changes and scarring
• Nail deformities
• Ocular complications (severe cases may lead to blindness)
• Respiratory problems (including bronchiolitis obliterans)
• Urogenital problems 1, 3

Early recognition of these clinical features is crucial as SJS/TEN represents a true medical emergency with mortality rates up to 30% 2. Prompt diagnosis and management significantly improve outcomes.