| • | self-limited; relatively common |
| • | usually mild and relapsing |
| • | variety of lesions (blisters, target shaped urticarial plaques) |
| • | mucous membranes: 70% of patients, almost exclusively limited to oral cavity |
pathogenesis:
| • | currently seen as a cell-mediated immune reaction aimed at the destruction of keratinocytes expressing HSV antigen |
| • | herpes simplex (recurrent EM) |
clincal:
| • | prodromal symptoms are usually absent; afebrile |
| • | skin rash arises abruptly (usually, all lesions appear within 3 days) |
| • | not all lesions typical: |
| • | some with only 2 rings (i.e. raised atypical targets) |
| • | bullous EM - blister secondary to necrosis |
| • | herpes iris of Batemen: larger lesions with central bullae and a marginal ring of vesicles |
| • | but flat lesion, typical of SJS-TEN are not found |
prognosis:
| • | spontaneously resolves in 1 to 4 weeks |
| • | progression to SJS/TEN does not occur |
treatment:
| • | in patients with a well defined interval between their HSV episode and onset of EM, a 5 day course of acyclovir (400mg BID) will prevent EM in most cases |
| • | continuous administration of low dose acyclovir effectively prevents episodes of both HSV and EM as long as treatment is continued |
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