What characterizes Toxic Epidermal Necrolysis (TEN)?

Toxic Epidermal Necrolysis (TEN) is characterized primarily by significant mucous membrane involvement. This systemic condition typically manifests with widespread erythema and detachment of the epidermis, affecting not only the skin but also the mucosal surfaces such as the eyes, mouth, and genitals. The lesions can be extensive, leading to serious complications and requiring hospitalization.

One key feature distinguishing TEN from other similar conditions, such as Stevens-Johnson syndrome (SJS), is the severity and extent of mucosal involvement. In TEN, the presence of oral lesions, conjunctivitis, and other mucosal erosions is common and constitutes a critical aspect of the disease's presentation.

While other symptoms, such as fever and possibly a positive Nikolsky sign (which denotes skin fragility), may be present in TEN, these features are not as definitive for the diagnosis. A positive Nikolsky sign indicates that the epidermis can be easily detached from the dermis with lateral pressure, but it is common in other blistering disorders as well.

The extent of epidermal detachment in TEN is generally greater than 30%, distinguishing it from conditions like SJS, where the percentage is less than 10%. Therefore, the presence of mucous membrane involvement