Erythema multiforme

Alternate names

EM; Erythema polymorphe, erythema multiforme type; Erythema multiforme bullosum; Dermatostomatitis, erythema multiforme type; Febrile mucocutaneous syndrome; Herpes iris, erythema multiforme type

Definition

Erythema multiforme (EM) refers to a group of hypersensitivity disorders characterized by symmetric red, patchy lesions, primarily on the arms and legs.

Summary

A hypersensitivity reaction characterized by the sudden appearance of symmetrical cutaneous and mucocutaneous macular or papular lesions which evolve into lesions with bright red borders (target lesions). The lesions usually appear in the hands, feet, extremities, and face. Symptoms include fever, malaise, sore throat, cough, vomiting, diarrhea, arthralgia, and myalgia. Causes include infections (most commonly herpes simplex virus), drugs (e.G., sulfonamides, anticonvulsants, and antibiotics), malignancies, and collagen vascular disorders.

Cause

EM is a type of allergic reaction. In most cases, it occurs in response to an infection. In rare cases, it is caused by certain medicines or body-wide (systemic) illness.

Infections that may lead to EM include:

• Viruses, such as herpes simplex that cause cold sores and genital herpes (most common)
• Bacteria, such as Mycoplasma pneumoniae that cause lung infection
• Funguses, such as Histoplasma capsulatum, that cause histoplasmosis

Medicines that may cause EM include:

• NSAIDs
• Allopurinol (treats gout)
• Certain antibiotics, such as sulfonamides and aminopenicillins
• Anti-seizure medicines

Systemic illnesses that are associated with EM include:

• Inflammatory bowel disease, such as Crohn disease
• Systemic lupus erythematosus

EM occurs mostly in adults 20 to 40 years old. People with EM may have family members who have had EM as well.

Forms

There are two forms of EM:

• EM minor usually involves the skin and sometimes mouth sores.
• EM major often starts with a fever and joint aches. Besides the skin sores and mouth sores, there may be sores in the eyes, genitals, lung airways, or gut.

Signs and symptoms

Symptoms of EM include:

• Low-grade fever
• Headache
• Sore throat
• Cough
• Runny nose
• General ill feeling
• Itchy skin
• Joint aches
• Many skin lesions (sores or abnormal areas)

Skin sores may:

• Start quickly
• Come back
• Spread
• Be raised or discolored
• Look like hives
• Have a central sore surrounded by pale red rings, also called a target, iris, or bulls-eye
• Have liquid-filled bumps or blisters of various sizes
• Be located on the upper body, legs, arms, palms, hands, or feet
• Include the face or lips
• Appear evenly on both sides of the body (symmetrical)

Other symptoms may include:

• Bloodshot eyes
• Dry eyes
• Eye burning, itching, and discharge
• Eye pain
• Mouth sores
• Vision problems

Diagnosis

Tests may include:

• Skin lesion biopsy
• Examination of skin tissue under a microscope

Treatment

EM usually goes away on its own with or without treatment.

Treatment may include:

• Medicines, such as antihistamines, to control itching
• Moist compresses applied to the skin
• Pain medicines to reduce fever and discomfort
• Mouthwashes to ease discomfort of mouth sores that interferes with eating and drinking
• Antibiotics for skin infections
• Corticosteroids to control inflammation
• Medicines for eye symptoms
• Good hygiene may help prevent secondary infections (infections that occur from treating the first infection).
• Use of sunscreen, protective clothing, and avoiding excessive exposure to sun may prevent the recurrence of EM.

Prognosis

Mild forms of EM usually get better in 2 to 6 weeks, but the problem may return.

Gallery

• 
  The left arm on the 3rd day after starting erythema exudativum multiforme
• 
  Fox Plate XXXII
• 
  Drug eruption
• 
  Erythema multiforme on legs

NIH genetic and rare disease info

• NIH info on Erythema multiforme

Erythema multiforme is a rare disease.

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