<\/span><\/h2>\nErythema multiforme most commonly affects young adults (20\u201340 years of age), however all age groups and races can be affected. There is a male predominance.<\/p>\n
There's a genetic<\/span> tendency to erythema multiforme. Certain types of tissue are found more often in people with herpes-associated erythema multiforme (HLA<\/span>-DQw3) and recurrent<\/span> erythema multiforme (HLA-B15, -B35, -A33, -DR53, -DQB1*0301).<\/p>\n\n
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<\/span>What triggers erythema multiforme?<\/span><\/h2>\n<\/span>Infections<\/span><\/h3>\nInfections are probably associated with at least 90% of erythema multiforme cases.<\/p>\n
The most common trigger for developing erythema multiforme is the herpes simplex virus (HSV) infection<\/span>, usually herpes labialis (cold sores on the lip) and less frequently genital herpes. HSV type 1 is more commonly associated than type 2. Herpes infection usually precedes skin rash by 3\u201314 days.<\/p>\nMycoplasma pneumonia (a lung infection caused by bacteria<\/span> Mycoplasma pneumoniae<\/em>) is the next most common trigger.<\/p>\nMany different virus infections have been reported to trigger erythema multiforme, including:<\/p>\n
\n- Parapoxvirus (orf and milkers nodules<\/span>)<\/li>\n
- Herpes varicella-zoster (chicken pox, shingles)<\/li>\n
- Adenoviruses<\/li>\n
- Hepatitis<\/span> virus<\/li>\n
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Human immunodeficiency virus (HIV<\/span>)<\/li>\n- Cytomegalovirus<\/li>\n
- viral vaccines\n<\/li>\n<\/ul>\n
Dermatophyte fungal infections (ringworm) have also been reported in association with erythema multiforme.<\/p>\n
<\/span>Drugs<\/span><\/h3>\nMedications are probably a rare cause (<10%) de eritema multiforme. Si este diagn\u00f3stico se est\u00e1 considerando seriamente, entonces el medicamento alternativo rashes<\/span> should be excluded, such as SJS\/TEN, generalized<\/span> fixed Drug Rash, polymorphic<\/span> exanthematous<\/span> drug eruption and urticaria<\/span>.<\/p>\nMany drugs have been reported to trigger erythema multiforme, including barbiturates, non-steroidal anti-steroids.inflammatory<\/span> drugs, penicillins, sulfonamides, nitrofurantoin, phenothiazines, and anticonvulsants.<\/p>\n<\/span>Clinical features of erythema multiforme.<\/span><\/h2>\n<\/span>general symptoms<\/span><\/h3>\nThere is usually no prodromal<\/span> symptoms in erythema multiforme minor. However, erythema multiforme major may be preceded by mild symptoms such as fever<\/span> or chills, weakness, or joint pain.<\/p>\n<\/span>Skin lesions<\/span><\/h3>\nTypically, in erythema multiforme, a few to hundreds of skin lesions erupt in a 24-hour period. Lesions are first seen on the backs of the hands and\/or tops of the feet and then spread down the extremities toward the trunk. The upper limbs are more commonly affected than the lower limbs. The palms and soles may be involved. The face, neck, and trunk are common sites. Skin lesions are often grouped<\/span> on elbows and knees. There may be an associated mild itching or burning sensation.<\/p>\nThe initial lesions are acutely demarcated<\/span>, round, red\/pink and flat (macules<\/span>), which become raised (papules<\/span>\/ \/palpable<\/span>) and gradually expand to form plates<\/span> (raised flat patches) up to several centimeters in diameter. The center of the papule<\/span>\/ \/license plate<\/span> darkens in color and develops superficial (epidermal) changes such as blisters or crust<\/span>. The lesions generally evolve over 72 hours.<\/p>\nThe typical target lesion<\/span> (also called iris injury<\/span>) of erythema multiforme has a sharp margin, a regular round shape, and three concentric color zones:<\/p>\n\n- The center is dark or dark red with a blister or Cortex<\/span>\n<\/li>\n
- The next ring is a paler pink and is raised due to edema<\/span> (fluid swelling)<\/li>\n
- The outermost ring is bright red.<\/li>\n<\/ul>\n
Atypical<\/span> target lesions show only two zones and\/or an indistinct border.<\/p>\nThe rash is polymorphous<\/span> (many forms), hence the "multiform" in the name. Lesions may be in various stages of development with typical and atypical targets present at the same time. A full skin exam may be required to find typical targets, as these may be few in number.<\/p>\nThe lesions show Kobner<\/span> (isomorphic<\/span>) phenomenon, which means that they can develop in previous sites (but not concurrent<\/span> or later) skin trauma<\/span>.<\/p>\nThere is no associated swelling of the face, hands, or feet, despite being common sites of eruption<\/span> distribution<\/span>. However, the lips are often swollen, especially in erythema multiforme major.<\/p>\n\n<\/span>Erythema multiforme<\/span><\/h5>\n<\/section>\n\n\n
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Erythema multiforme<\/p>\n
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Target injuries<\/p>\n
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Target injuries<\/p>\n<\/p><\/div>\n<\/section>\n
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See more images of erythema multiforme.<\/p>\n
<\/span>\nMucous membrane<\/span> intervention<\/span><\/h3>\nMucous membrane<\/span> Lesions, if present, usually develop a few days after the rash begins.<\/p>\nIn erythema multiforme minor, mucous membrane involvement is absent or mild. Mucosal changes, if present, initially consist of redness of the lips and inside the cheek. Blisters sometimes develop and quickly rupture to form erosions<\/span> and ulcers<\/span>.<\/p>\nIn erythema multiforme major, one or more mucous membranes<\/span> are usually affected, most often the oral mucous membrane<\/span>:<\/p>\n