Table 2.

Description of AGEP and TEN

	AGEP	TEN
Incidence	1–5/million/year	2–7/million/year
Etiology	Drug (90%) viral, bacterial, or parasitic infections spider bites	Drug (60%) M. pneumoniae infections 1/3 cases no cause
Clinical presentation
Distribution pattern	Intertriginous (generalized)	Generalized
Mucous Membrane	20% (oral)	100% (> 30%)
Pustules	Yes	No
Target lesions	No	Yes
Nikolsky sign	Rare	Yes
Fever	Yes	Yes
Timing	Hours–days	Days–weeks (< 8 wks)
Clinical course	Resolution/re-epithelialization 2-4 weeks
Histological features	Spongiform subcorneal and/or intraepidermal pustules edema of the dermis, necrosis of single keratinocytes, and an inflammatory infiltrate of neutrophils and eosinophils with perivascular accentuation	Keratinocyte necrosis (partial to full-thickness necrosis of all epidermis layers) perivascular, discrete lymphohistiocytic, inflammatory infiltrate (some eosinophils) in the superficial dermis, ± subepidermal bullae
Prognosis (mortality)	Resolution 2–4 weeks	Acute phase 8–12 days Mortality 30%
Treatment	d/c drug	d/c drug PO or IV corticosteroids, IV immunoglobulin, cyclosporin, anti-TNF