What is the distinction between Toxic Epidermal Necrolysis (TEN) and Staphylococcal Scalded Skin Syndrome (SSSS) based on?

Distinction Between Toxic Epidermal Necrolysis and Staphylococcal Scalded Skin Syndrome

The key distinction between Toxic Epidermal Necrolysis (TEN) and Staphylococcal Scalded Skin Syndrome (SSSS) is based on the level of exfoliation (cleavage plane), with SSSS having intraepidermal cleavage at the granular layer and TEN having subepidermal cleavage. 1

Clinical and Histopathological Differences

Cleavage Plane (Level of Exfoliation)

• In SSSS, skin detachment occurs at the granular layer (superficial part of the epidermis), resulting in intraepidermal cleavage 1, 2
• In TEN, necrotic epidermis separates from the underlying dermis, producing a subepidermal cleavage 1, 2
• This difference in cleavage plane can be confirmed by skin biopsy or frozen section of a blister roof to distinguish between the conditions 1

Mucosal Involvement

• TEN typically presents with prominent mucosal involvement of eyes, mouth, nose, and genitalia, leading to erosive and hemorrhagic mucositis 1
• SSSS characteristically lacks mucosal involvement, which is a key clinical feature that distinguishes it from TEN 1

Etiology

• TEN is usually triggered by drugs (particularly sulfonamide antibiotics, barbiturates, carbamazepine, and allopurinol) and rarely by infections 3
• SSSS is caused by circulating bacterial exotoxins (exfoliative toxins) produced by phage group II Staphylococcus aureus 4, 5

Age Distribution

• SSSS occurs primarily in children, especially newborns and infants 4, 5
• TEN affects all age groups, with mortality being higher in adults than in children 1, 3

Pathogenesis

• In SSSS, exfoliative toxins (serine proteases) are spread hematogenously from a localized infection site, targeting desmoglein 1 and causing widespread epidermal damage 4, 5
• In TEN, there is extensive epidermal necrosis with basal cell vacuolar degeneration, resulting from an immune-mediated reaction 1

Diagnostic Approach

When to Suspect Each Condition

• Consider TEN when there is:
  • Presence of cutaneous pain as an early feature 1
  • Mucosal involvement (eyes, mouth, nose, genitalia) 1
  • History of recent drug exposure (1-3 weeks prior) 3
• Consider SSSS when there is:
  • Abrupt onset of diffuse erythema and fever 4
  • Absence of mucosal involvement 1
  • Predominantly affecting young children 4, 5

Confirmatory Testing

• Skin biopsy with histopathological examination is the definitive method to distinguish between these conditions 1
• Frozen section processing can expedite diagnosis in urgent cases 4, 5

Clinical Implications and Management

Prognosis

• SSSS generally has a better prognosis with rapid recovery due to the high cleavage plane that only transiently disrupts the skin barrier 5
• TEN has a higher mortality rate (approximately 30%), especially in adults 6

Treatment Differences

• SSSS requires appropriate anti-staphylococcal antibiotics targeting the causative organism 4
• TEN management includes immediate discontinuation of the culprit drug and supportive care similar to burn management 1, 6

Common Pitfalls

• Misdiagnosing one condition for the other can lead to inappropriate treatment strategies 1
• Failure to perform a skin biopsy when the diagnosis is uncertain may delay appropriate management 1
• Not recognizing the absence of mucosal involvement as a key distinguishing feature of SSSS 1