Erythema multiforme EM is a rare skin disorder that mainly affects children. When seen in adults, it usually occurs between the ages of 20 and 40, although it can happen to people of any age. Men tend to experience erythema multiforme more frequently than women. This is called erythema multiforme minor. This type is called erythema multiforme major and makes up about 20 percent of cases.
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DermNet provides Google Translate, a free machine translation service. Note that this may not provide an exact translation in all languages. Updated by Dr Delwyn Dyall-Smith, Further updated by Dr Amanda Oakley, October Erythema multiforme is a hypersensitivity reaction usually triggered by infections , most commonly herpes simplex virus HSV. It presents with a skin eruption characterised by a typical target lesion. There may be mucous membrane involvement. It is acute and self-limiting, usually resolving without complications.
Erythema multiforme is divided into major and minor forms and is now regarded as distinct from Stevens—Johnson syndrome SJS and toxic epidermal necrolysis TEN. Erythema multiforme most commonly affects young adults 20—40 years of age , however, all age groups and races can be affected. There is a male predominance. There is a genetic tendency to erythema multiforme. The single most common trigger for developing erythema multiforme is herpes simplex virus HSV infection , usually herpes labialis cold sore on the lip and less often genital herpes.
HSV type 1 is more commonly associated than type 2. The herpes infection usually precedes the skin eruption by 3—14 days. Mycoplasma pneumonia a lung infection caused by the bacteria Mycoplasma pneumoniae is the next most common trigger. Dermatophyte fungal infections tinea have also been reported in association with erythema multiforme.
Many drugs have been reported to trigger erythema multiforme, including barbiturates, non-steroidal anti- inflammatory drugs , penicillins , sulphonamides, nitrofurantoin, phenothiazines, and anticonvulsants. There are usually no prodromal symptoms in erythema multiforme minor. However, erythema multiforme major may be preceded by mild symptoms such as fever or chills, weakness or painful joints. Typically in erythema multiforme, few to hundreds of skin lesions erupt within a hour period. The upper limbs are more commonly affected than the lower.
Palms and soles may be involved. The face, neck and trunk are common sites. Skin lesions are often grouped on elbows and knees. There may be an associated mild itch or burning sensation. Lesions usually evolve over 72 hours. The typical target lesion also called iris lesion of erythema multiforme has a sharp margin, regular round shape and three concentric colour zones:. Lesions may be at various stages of development with both typical and atypical targets present at the same time.
A full skin examination may be required to find typical targets, as these may be few in number. There is no associated swelling of face, hands or feet, despite these being common sites of rash distribution. However, the lips are often swollen, especially in erythema multiforme major. Mucosal lesions, if present, typically develop a few days after the skin rash begins.
In erythema multiforme minor, mucous membrane involvement is absent or mild. Mucosal changes, if present, consist initially of redness of the lips and inside the cheek. Sometimes blisters develop and quickly break to form erosions and ulcers.
In erythema multiforme major, one or more mucous membranes are typically affected, most often the oral mucosa :. Mucosal lesions consist of swelling and redness with blister formation.
The blisters break quickly to leave large, shallow, irregular shaped, painful ulcers that are covered by a whitish pseudomembrane. Typically the lips are swollen with haemorrhagic crusts. The patient may have difficulty speaking or swallowing due to pain. With mycoplasma pneumonia , the mucous membranes may be the only affected sites mucositis.
This can be severe and require hospitalisation due to difficulty eating and drinking. Whether this is a limited form of erythema multiforme has not been determined. It is also known as Fuchs syndrome, and mucosal erythema multiforme may occasionally be due to recurrent herpes simplex. Erythema multiforme can be recurrent, with multiple episodes per year for many years. This is believed to be nearly always due to HSV-1 infection. Erythema multiforme is a clinical diagnosis, although skin biopsy may be required to exclude other conditions.
The histology of erythema multiforme is characteristic but not diagnostic. It varies with the age of the lesion, its appearance, and which part is biopsied. Other tests may be done looking for infections commonly seen in association with erythema multiforme, such as mycoplasma.
For the majority of cases, no treatment is required, as the rash settles by itself over several weeks without complications. Treatment directed to any possible cause may be required such as oral aciclovir not topical for HSV or antibiotics eg, erythromycin for Mycoplasma pneumoniae. If a drug cause is suspected then the possible offending drug should be ceased. The role of oral corticosteroids remains controversial, as no controlled studies have shown any benefit.
However for severe disease 0. This has been shown to be effective in placebo -controlled double-blind studies. However, erythema multiforme may recur when the aciclovir is ceased.
Other treatments used continuously that have been reported to help suppress recurrent erythema multiforme include:. Erythema multiforme minor usually resolves spontaneously without scarring over 2—3 weeks. Erythema multiforme major can take up to 6 weeks to resolve. There may be residual mottled skin discolouration. Significant eye involvement in erythema multiforme major may rarely result in serious problems, including blindness.
See smartphone apps to check your skin. DermNet NZ does not provide an online consultation service. If you have any concerns with your skin or its treatment, see a dermatologist for advice. Erythema multiforme — codes and concepts open. EM, Erythema multiforme minor, Erythema multiforme major. Reaction to external agent, Viral infection. Causes of erythema multiforme, Role of HSV in erythema multiforme, Clinical features of erythema multiforme including skin and mucous membranes, Recurrent erythema multiforme, Diagnosis of erythema multiforme, Treatment of erythema multiforme.
L51, L Z, DA Erythema multiforme and related disorders. Severe cutaneous adverse reactions. Correlations between clinical patterns and causes of erythema multiforme majus, Stevens-Johnson syndrome, and toxic epidermal necrolysis: results of an international prospective study.
Arch Dermatol ; — French LE, Prins C. Erythema multiforme, Stevens—Johnson syndrome and toxic epidermal necrolysis.
In Bolognia, Dermatology, 2nd edn. Erythema multiforme. Am Fam Physician ; —8. Erythema multiforme due to Mycoplasma pneumoniae infection in two children. Pediatr Dermatol ; —
Erythema Multiforme Information and Treatment
DermNet provides Google Translate, a free machine translation service. Note that this may not provide an exact translation in all languages. Updated by Dr Delwyn Dyall-Smith, Further updated by Dr Amanda Oakley, October Erythema multiforme is a hypersensitivity reaction usually triggered by infections , most commonly herpes simplex virus HSV. It presents with a skin eruption characterised by a typical target lesion.
What to know about erythema multiforme
Erythema multiforme is a skin immune reaction that an infection or medication can trigger. Erythema multiforme can affect people of any age, with children representing 20 percent of cases. However, it most commonly occurs in young adults between 20 and 30 years old. It is more prevalent in men, affecting five men for every one woman. Erythema multiforme can be minor or major. Erythema multiforme minor is usually a mild condition that causes a skin rash. Erythema multiforme major can be more severe and typically requires more extensive treatment.
NCBI Bookshelf. Wissem Hafsi ; Talel Badri. Authors Wissem Hafsi 1 ; Talel Badri 2. Its causes are variable and numerous, and its evolution is generally favorable. More rarely, and in a more questionable way, vaccines have been incriminated. EM is reported worldwide without any ethnic predilection. It is more common in men with a sex ratio of 1 in 5.