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Erythema multiforme

Essential points for quick revision.

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Suspected SJS or severe mucosal compromise

Skin pain, rapidly spreading dusky macules or flat atypical targets, blistering or detachment, fever and severe involvement of two or more mucosal sites after a medicine are not routine erythema multiforme; dehydration, ocular injury and airway or genital scarring can evolve quickly.

Action: Stop any suspect non-essential medicine, assess airway, eyes, mouth, genital and urinary function and arrange emergency hospital and dermatology review with supportive resuscitation; obtain ophthalmology and other site-specific specialist input early rather than waiting for extensive detachment.

Synopsis

Recognise true target lesions and mucosal severity across skin tones, identify infection-related triggers, separate erythema multiforme from Stevens–Johnson syndrome, and treat acute and recurrent disease safely.

  • A classic erythema-multiforme target is a fixed round lesion with three concentric zones: a dusky or blistered centre, a paler oedematous ring and a sharply defined outer erythematous rim.
  • Lesions arise symmetrically on backs of hands, feet and extensor limbs and spread centripetally; they remain in the same place for days, unlike individual urticarial wheals.
  • On brown or black skin, the outer ring may be purple-brown and central duskiness grey or deep brown; palpability, oedema, blistering and the concentric outline may be clearer than red colour.

Key red flags

Skin pain, systemic toxicity, rapidly expanding central duskiness, epidermal detachment, inability to drink, reduced urine, breathing difficulty, visual symptoms, genital erosions, pregnancy, immunosuppression or diagnostic uncertainty requires same-day specialist assessment.

Mucosal erythema multiforme

Painful oral erosions and haemorrhagic lip crust can accompany classic skin targets; ocular, genital or airway symptoms increase severity and referral need.

Investigation priorities

01
Whole-skin and mucosal examinationFirst step

Confirm target morphology, map severity and identify an SJS or TEN pattern.

Management branches

First diagnostic sequenceVerify targets before naming the eruption

A sudden symmetrical annular or targetoid eruption is reported.

  1. Establish whether individual lesions are fixed for days and have three palpable zones, then map acral versus truncal distribution and photograph representative sites with consent.
  2. Examine all mucosae, measure skin pain and detachment and record systemic observations before asking about HSV, respiratory infection and a complete medicine timeline.
First-line limited careRelieve symptoms and remove the active trigger

Classic targets are limited, the patient is systemically well and oral intake is secure.

Key medicines

Site-appropriate topical corticosteroidApply a thin layer once daily to inflamed intact target plaques for up to seven to fourteen days, selecting potency by site and reviewing if blistering or spread continues.
Aciclovir recurrent-disease suppressionTake 400 mg by mouth twice daily continuously for at least six months when recurrent HSV-associated erythema multiforme is confirmed, then review the need for continuation.
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Sources and review status4 sources · checked 27 Aug 2026 · clinical review pending
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom