Staphylococcal Scalded Skin Syndrome (SSSS)

Overview

Epidemiology

• Primarily a disease of children
• Incidence (in the United States): 
  • 8 cases per 1 million children
  • 1 case per 1 million adults
• Demographics:
  • Most patients are < 2 years of age.
  • Rare in adults
  • Boys > girls
• Mortality: 
  • 1%–5% in children
  • 50%–60% in adults

Etiology

• Causative organism: exfoliative toxin-producing strains of Staphylococcus aureus:
  • Gram-positive cocci in clusters
  • Coagulase-positive
  • Exfoliative toxin is produced in approximately 5% of S. aureus strains.
  • Most common strains: types 55 and 71
• Transmission: contact with an asymptomatic or colonized carrier
• Common sites of outbreaks:
  • ICUs
  • Nurseries
• Risk factors:
  • Children are more vulnerable because of:
    • Lack of immunity
    • Immature renal clearance (exotoxin cleared through the kidneys)
  • Adults:
    • Immunodeficiency
    • Renal failure
    • Malignancy
    • Diabetes

Pathophysiology

• Starts as a localized, staphylococcal infection: 
  • Skin wounds
  • Conjunctivitis
  • Pharyngitis
  • Pneumonia
  • The primary site of infection is not always evident.
• Staphylococcus produces exotoxin → spread hematogenously
  • Two types of exotoxins:
    • Exfoliative toxin A
    • Exfoliative toxin B
  • Exotoxin function: 
    • Cleaves desmoglein (Dsg) 1 complex in the stratum granulosum
    • Disrupts keratinocyte-to-keratinocyte adhesion
    • Causes separation and detachment of the superficial epidermis

Clinical Presentation

• Incubation period: 1–10 days
• Prodromal symptoms:
  • Fever
  • Irritability
  • Malaise
  • Poor feeding 
• Sites of primary infection:
  • Infants: umbilical stump or diaper region
  • Older children: face
  • Frequently not evident
• Cutaneous findings:
  • Early manifestations:
    • Erythematous macules on the face and flexural surfaces (e.g., axilla, inguinal folds, gluteal cleft)
    • Skin pain
  • Erythema spreads diffusely within 24–48 hours.
    • Resembles an acute burn
    • Flaccid blisters develop, creating a wrinkled appearance.
    • Skin peeling and erosions in areas of friction with red, moist skin underneath
    • Positive Nikolsky’s sign: extension of skin blistering or sloughing by applying pressure
    • Fissures and crusting around the mouth, eyes, and nose (called “SSSS sad face”)
    • Spares the mucosa
  • Widespread desquamation may take place within 36–72 hours.
  • Healing occurs within 2 weeks.
• The loss of the skin barrier predisposes patients to:
  • Dehydration
  • Electrolyte imbalances
  • Sepsis
  • Hypothermia

Diagnosis and Management

Diagnosis

• Usually diagnosed clinically
• Cultures:
  • Used for confirmation and antibiotic susceptibility data
  • Should not be taken from bullae: Site will be sterile, since condition is caused by a toxin.
  • Options:
    • Possible areas of a primary infection
    • Conjunctiva
    • Nares
    • Nasopharynx
    • Blood
• Biopsy: 
  • Can be used for confirmation if the diagnosis is unclear.
  • Findings:
    • Superficial epidermal splitting
    • Noninflammatory 
• Supporting workup:
  • Leukocytosis
  • ↑ ESR
  • Basic metabolic panel → assess for dehydration and electrolyte imbalances
  • Chest radiography → rule out staphylococcal pneumonia as the originating source

Management

Management of SSSS includes aggressive treatment of primary infection and supportive care.

• Supportive measures: 
  • Hospital admission:
    • Burn unit (if available) for severe cases
    • Intensive care unit
  • IV fluid hydration
  • Monitor and replace electrolytes
  • Gentle skin and wound care
  • Analgesia
• IV antibiotics should be initiated upon suspicion of the diagnosis: 
  • For coverage of methicillin-sensitive S. aureus (MSSA):
    • Oxacillin
    • Nafcillin
    • Cefazolin
  • For coverage of methicillin-resistant S. aureus (MRSA):
    • Vancomycin
    • Linezolid
  • Clindamycin may be added in severe cases:
    • May ↓ toxin production
    • Evidence is lacking

Differential Diagnosis

• Stevens–Johnson syndrome: a cutaneous, immune-mediated hypersensitivity reaction that is commonly triggered by medications: Stevens–Johnson syndrome runs on a spectrum with toxic epidermal necrolysis and is characterized by keratinocyte necrosis and separation of the epidermis from the dermis. Patients will present with a flu-like prodrome, followed by cutaneous bullae and sloughing. Unlike SSSS, the mucous membranes are involved. Management is largely supportive, and withdrawal of the causative agent is required.
• Bullous impetigo: a superficial skin infection caused by Streptococcus or Staphylococcus: Unlike SSSS, the exotoxin remains localized and does not spread. Bullous impetigo is commonly seen in children and manifests as clusters of vesicles that quickly enlarge and form bullae. After the bullae burst, the exposed bases become covered with a honey-colored crust. The diagnosis is clinical, but cultures may be obtained from the lesions if the patient does not respond to antibiotic therapy.
• Bullous pemphigoid: an autoimmune blistering disease caused by antibodies against hemidesmosomes: Patients are usually elderly and present with pruritic, tense, bullous lesions and spared mucosal surfaces. Triggers include medications, trauma, skin conditions, and systemic disease. Biopsy with immunofluorescent staining is used for the diagnosis. Management includes steroids, immunosuppressants, and antiinflammatory medications.
• Pemphigus vulgaris: an autoimmune disorder due to antibodies against desmoglein 1 and 3, causing intraepidermal blistering and erosions of the skin and mucous membranes: Patients will have cutaneous bullae appearing on normal-appearing skin and painful mucocutaneous erosions. Diagnosis is by biopsy with immunofluorescent staining. Blistering occurs lower in the epidermis than occurs with SSSS. Management includes corticosteroids, immunosuppressants, and IV immunoglobulin.
• Exfoliative dermatitis: a generalized, symmetric, erythematous, scaling rash caused by an underlying cutaneous diseases (psoriasis, atopic dermatitis), medications, and malignancy (lymphoma): Unlike SSSS, bullae are not typically seen and the Nikolsky sign is negative. Diagnosis is made clinically, and management focuses on treating the underlying cause, withdrawal of implicated medications, and supportive care.
• Toxic shock syndrome: a systemic syndrome caused by Staphylococcus or Streptococcus endotoxins: Patients present with fever, shock, and multisystem organ dysfunction, which are not seen in SSSS. Cutaneous manifestations include a diffuse, erythematous rash and desquamation. Diagnosis is based on blood culture results, the clinical history, and the exam. Management includes hemodynamic support, fluid resuscitation, and antibiotics.