Erythema multiforme



Erythema multiforme


Jean Revuz


Evidence Levels:  A Double-blind study  B Clinical trial ≥ 20 subjects  C Clinical trial < 20 subjects  D Series ≥ 5 subjects  E Anecdotal case reports


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Erythema multiforme (EM) is a distinct cutaneous reaction pattern to a variety of stimuli, predominantly herpes simplex virus (HSV) infection. It usually runs a self-limiting course but has a tendency to recur. It is defined by the presence of ‘typical’ three-zone target lesions, with a predominantly acral distribution. The presence of mucosal involvement at more than one site distinguishes EM major from EM minor. A specific variant has mucosal lesions only, without skin involvement. EM major can be distinguished from Stevens–Johnson syndrome which lacks typical target-like lesions and acral location but, instead, irregular macule or atypical targets and a truncal location. EM is frequently misdiagnosed in cases of urticaria and more rarely in cases of cutaneous lupus, vasculitis, erythema annulare, and drug eruption.



Management strategy


In 30–50% of cases the etiology of EM is unknown. The most commonly recognized precipitant is HSV infection, both types I and II. HSV-specific DNA has been isolated from lesional tissue in 60–70% of cases. HSV particles are found in the circulating precursors of epidermal Langerhans cells. A variety of other viral infections (orf, VZV, EBV, CMV, HIV), bacterial infections (mainly Mycoplasma pneumoniae), and fungal infections (mainly histoplasmosis), have been implicated. An extensive list of drugs have been reported to trigger EM but most cases if not all are the result of a confusion with Stevens-Johnson syndrome. Rare cases are attributed to contact allergy.


Acute episodes of EM need only symptomatic treatment in most cases. Recurrent EM which may severely affect quality of life has a well-recognized preventive treatment in case of HSV infection.


There are no double-blind or open trials of treatments for acute episodes of EM. Most cases, particularly EM minor, run a self-limiting course. Symptomatic measures include oral antihistamines and mild- to moderate-potency topical corticosteroids to reduce pruritus. Underlying conditions, mainly Mycoplasma pneumoniae infection, should be treated. Recurrent EM (>6 attacks per year) may respond to long-term acyclovir. In acyclovir-resistant cases a variety of other therapies can be helpful (see below).


Mucosal manifestations of EM are a source of morbidity and occur in up to 70% of cases. The commonest sites affected are the buccal mucosa and lips. Symptomatic measures include mouthwashes, a soft diet, topical anesthetics (lidocaine gel, benzocaine lozenges or 0.15% benzydamine hydrochloride), and topical corticosteroids (e.g., 0.1% triamcinolone acetonide paste). Budesonide or beclomethasone inhalers (one puff three to four times daily) provide an alternative method of delivering local corticosteroid to the inflamed mucosal surfaces. Short courses of high-dose oral prednisolone may be needed for severe oral disease. Strict eye care to reduce secondary infection and scarring includes saline washes for removal of crusts, local antibiotics, and frequent debridement of tarsal and bulbar conjunctival adherences.




First-line therapies









image Acyclovir A








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Aug 7, 2016 | Posted by in Dermatology | Comments Off on Erythema multiforme

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