220.127.116.11 Toxic Epidermal Necrolysis
Grading & Level of Importance: C
Rare disease 1-2 per 1 million. Higher risk in HIV/AIDS.
Severe drug-induced skin reaction characterised by death of the epidermis (keratinocyte necrosis) and marked mucosal erosions. Part of a spectrum, which ranges from SJS, where 30% of the BS is referred to as SJS-TEN-overlap syndrome.
Aetiology & Pathogenesis
Triggers are medications (typically antibiotics and antiepileptic drugs). Immunologically-induced apoptosis of keratinocytes cascading unchecked into massive epidermal destruction may be the pathogenic mechanism. Necrolysis by TNF alpha and gamma IFN. AnnexinA 1 promotes apotosis of keratinocyes. Increased miR-18 a-5p which is blocking antiapotopic action.
Signs & Symptoms
Starting with a confluent maculopapular exanthem without the classical E.e.m. like lesions, haemorrhagic blisters, epidermal necrosis followed by loss of sheets of epidermis; positive Nikolski's signs (Nikolski I: blisters induced by rubbing normal skin. Nikolski II: existing blisters extend with lateral pressure); usually severe periorificial mucosal erosions.
Skin and mucosa.
Part of the Erythema multiforme –SJS/TEN complex as the maximal variant of the clinical cascade.
Laboratory & other workups
Check electrolytes, kidney and liver parameters, cardiac function.
Cytotoxic CD8 T-lymphocytes attacking the epidermal keratinocytes, but also mucous epithelia. Apoptosis and necrosis of cells. Disruption of epidermal / dermal connection. Bulla formation because of severe epidermal necrosis. Epidermal remnants separated from dermis with only sparse inflammatory infiltrate.
More than 40 % complications. 30% mortality rate. More than 50% of TEN patients suffer from long-term sequelae.
Infection, electrolyte and fluid disturbances. Ophthalmic involvement incl. ectropium and synechia, phimosis, vaginal synechia. Scarring in esophagus and mouth mucosa.
SCORTEN evaluation essential.
Clinical features and histology, showing necrolysis throughout all epidermal layers.
Prevention & Therapy
Immediate referral to special dermatologic and intensive care center.
Aggressive burn therapy (fluid and electrolyte management, appropriate antibiotic coverage, warming measures), special supportive.
According to course and BS and mucosal involvement. Intravenous immunoglobulins, TNF alpha blockers. High dose ciclosporine and / or systemic corticosteroids. Ophthalmology review.
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