36 Ulcers and erosions: Erythema multiforme, toxic epidermal necrolysis and Stevens-Johnson syndrome

36 Ulcers and erosions: Erythema multiforme, toxic epidermal necrolysis and Stevens-Johnson syndrome

Figure 36.1 Erythema multiforme etiology.

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Figure 36.2 Erythema multiforme pathogenesis.

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Figure 36.3 Erythema multiforme.

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Figure 36.4 Erythema multiforme.

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Figure 36.5 Erythema multiforme target lesions.

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Figure 36.6 Erythema multiforme treatment.

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Table 36.1 Main causal factors in erythema multiforme.

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Erythema multiforme

Definition: Erythema multiforme (EM) is a mucocutaneous condition mediated by antigen-antibody (immune complex – mainly IgM) deposition in the superficial microvasculature of skin and mucous membranes.

Prevalence (approximate): Uncommon.

Age mainly affected: Younger adults in second and third decades.

Gender mainly affected: M > F.

Etiopathogenesis: There may be a genetic predisposition, with various HLA associations (e.g. patients with extensive mucosal involvement may have HLA-DQB1*0402). A putative immunological hypersensitivity reaction usually to various micro-organisms or drugs (Figure 36.1) (Table 36.1), results in immune complexes and the ingress of cytotoxic CDimages T lymphocytes, inducing keratinocyte apoptosis and satellite cell necrosis (Figure 36.2).

Diagnostic features

EM minor (accounts for 80%) is a mild, self-limiting rash usually affecting one mucosa. EM major is a severe, life-threatening variant that overlaps with toxic epidermal necrolysis (see below) and involves m/>

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Jan 12, 2015 | Posted by in Oral and Maxillofacial Pathology | Comments Off on 36 Ulcers and erosions: Erythema multiforme, toxic epidermal necrolysis and Stevens-Johnson syndrome
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