Erythema multiforme

Definition

Erythema multiforme is a skin disorder that comes from an allergic reaction or infection.

Alternative Names

Lyell's syndrome; Stevens-Johnson syndrome; Erythema multiforme minor; Erythema multiforme major

Causes

Erythema multiforme is a type of hypsersensitivity reaction. It occurs in response to medicines, infections, or illness. Medications that can cause this reaction include:

• Barbiturates
• Penicillins
• Phenytoin
• Sulfonamides

Infections include:

• Herpes simplex
• Mycoplasma

The exact cause is unknown. The disorder may start with damage to the blood vessels of the skin, that is followed by damage to skin tissues.

Some forms of this condition are more severe than others.

• Erythema multiforme minor is not very serious. Most erythema multiforme is caused by herpes simplex or mycoplasma infections.
• Erythema multiforme major is more severe. It is also and is known as Stevens-Johnson syndrome. This form is usually caused by reactions to medicines, rather than infections.

Erythema multiforme occurs mostly in children and young adults.

Symptoms

• Fever
• General ill feeling
• Itching of the skin
• Joint aches
• Multiple skin lesions that:
  • Start quickly and may return
  • May spread
  • May appear as a nodule, papule, or macule and may look like hives
  • Have a central sore surrounded by pale red rings, also called a "target", "iris", or "bulls-eye"
  • May have vesicles and blisters of various sizes (bullae)
  • Are located on the upper body, legs, arms, palms, hands, or feet
  • May involve the face or lips
  • Are usually even on both sides (symmetrical)

Other symptoms may include:

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

Exams and Tests

You doctor will look at your skin to diagnose this problem and ask if you have a history of risk factors or related diseases.

Tests may include:

• Nikolsky's sign
• Skin lesion biopsy
• Examination of skin tissue undera microscope

Treatment

Treatment goals include:

• Controlling the illness that is causing the condition
• Preventing infection
• Treating the symptoms

Your doctor may have you stop taking any medicines that may be causing the problem. Do not stop taking medicines without talking to your doctor first. 

Treatment of mild symptoms may include:

• Medicines such as antihistamines to control itching
• Moist compresses applied to the skin
• Oral antiviral medicine if reaction is caused by herpes simplex
• Over-the-counter medications (such as acetaminophen) to reduce fever and discomfort
• Topical anesthetics (especially for mouth sores) to ease discomfort that interferes with eating and drinking

Treatment of severe symptoms may include:

• Antibiotics for skin infections
• Corticosteroids to control inflammation
•  treatment in an intensive care or burn care unit for severe cases, Stevens-Johnson syndrome, and toxic epidermal necrolysis
• Intravenous immunoglobulins (IVIG) to stop the disease process

Good hygiene and staying away from other people may help prevent secondary infections.

You may need skin grafting if  large areas of the body are affected.

Outlook (Prognosis)

Mild forms of erythema multiforme usually get better in 2 - 6 weeks, but the problem may return. More severe forms may be hard to treat. Stevens-Johnson syndrome and toxic epidermal necrolysis have high death rates.

Possible Complications

• Body-wide infection (sepsis)
• Loss of body fluids (shock)
• Occasionally, lesions on internal organs causing:
  • Heart inflammation (myocarditis)
  • Lung inflammation (pneumonitis)
  • Kidney inflammation (nephritis)
  • Liver inflammation (hepatitis)
• Permanent skin damage and scarring
• Skin infection (cellulitis)

When to Contact a Medical Professional

Go to the emergency room or call the local emergency number (such as 911) if you have symptoms of erythema multiforme. Get emergency help immediately if a large area of the body is affected.

References

In: Habif TP, ed. Clinical Dermatology. 5th ed. Philadelphia, Pa: Mosby Elsevier; 2009:chap 18.

Weber DJ, Cohen MS, Morrell DS, Rutala WA. The acutely ill patient with fever and rash. In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Disease. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 52.

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