Toxic Epidermal Necrolysis is characterized by a deeper split in the epidermis (i.e., at the dermoepidermal junction). The split in SSSS is instead higher, and just inferior to the stratum corneum (the uppermost layer of the epidermis).
Hence, SSSS lesions are more superficial and heal more quickly, while Toxic Epidermal Necrolysis is usually treated in burn units (which is crucial for survival: referral in less than 7 days after onset has a mortality rate of 4%, whereas referral beyond 7 days has a mortality rate of 83%). SSSS, on the other hand, is commonly treated with antibiotics, since it is induced by a staphylococcal toxin. Note that Toxic epidermal Necrolysis also is called toxic epidermal necrolysis of the Lyell type (from the British dermatologist who first described it) to distinguish it from toxic epidermal necrolysis of the Ritter type (from the Austrian dermatologist who described it in 1878)— another name for SSSS.
Hence, SSSS lesions are more superficial and heal more quickly, while Toxic Epidermal Necrolysis is usually treated in burn units (which is crucial for survival: referral in less than 7 days after onset has a mortality rate of 4%, whereas referral beyond 7 days has a mortality rate of 83%). SSSS, on the other hand, is commonly treated with antibiotics, since it is induced by a staphylococcal toxin. Note that Toxic epidermal Necrolysis also is called toxic epidermal necrolysis of the Lyell type (from the British dermatologist who first described it) to distinguish it from toxic epidermal necrolysis of the Ritter type (from the Austrian dermatologist who described it in 1878)— another name for SSSS.