Characteristics

AGEP

GPP

TEN

SJS

EMM

Age

Adults

Adults

Adults

Children and young adults (usually)

Young adults

Cause

Drugs, viral infections

Respiratory tract infection

Drugs

Drugs

Infection

Clinical Characteristics

Numerous small (<5mm) sterile pustules on edematous, erythematous skin, can involve mucous membranes

Confluent pustules on erythematous skin

Skin detachment  > 30% of body surface area, generalized, mucous membrane involvement

Skin detachment <10% of body surface area, widespread erythematous or purpuric macules or flat atypical targets, mucous membrane involvement

Typical and atypical target papules predominantly acrally distributed, no skin detachment, mucous membrane involvement

Fever

High

Prolonged

High

High

Absent or Mild

Leukocytosis

Yes

Yes

No (leukopenia)

No (leukopenia)

Mild elevation possible

Course

Self-limited, 5% mortality rate

Recurrent

Long term complications, can be fatal

Long term complications, can be fatal

Self-limited, resolves in 2 weeks

Histology

Spongy, subcorneal pustules, leukocytoclastic vasculitis, eosinophils

Spongy, subcorneal pustules, psoriaform acanthosis

Full-thickness epidermal necrosis with little dermal inflammation (mainly lymphocytes)

Full-thickness epidermal detachment with splitting above the basement membrane, and minimal inflammatory infiltrate

Dermal inflammation, apoptotic individual keratinocytes, spongiosis