Erythema multiforme is a skin disorder due to an allergic reaction or infection.

Erythema multiforme is a type of allergic reaction that occurs in response to medications, infections, or illness. Medications include:

• Barbiturates
• Penicillins
• Phenytoin
• Sulfonamides

Infections include:

• Herpes simplex
• Mycoplasma

Most erythema multiforme is associated with herpes simplex or mycoplasma infections.

The exact cause is unknown. The disorder is believed to involve damage to the blood vessels of the skin, followed by damage to skin tissues.

Some forms of this condition are more severe than others. Erythema multiforme minor is not very serious. Erythema multiforme major (also called Stevens-Johnson syndrome) is more severe. The more severe form is usually caused by reactions to medications, rather than infections.

Erythema multiforme occurs primarily in children and young adults.

• Fever
• General ill feeling
• Itching of the skin
• Joint aches
• Multiple skin lesions:
  • Start quickly and may return
  • May spread
  • May appear as a nodule, papule, or macule
  • Central lesion surrounded by pale red rings, also called a "target", "iris", or "bulls-eye"
  • May have vesicles and blisters of various sizes (bullae)
  • Located on the upper body, legs, arms, palms, hands, or feet
  • May involve the face or lips
  • Usually symmetrical

Other symptoms that may occur with this disease:

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

The diagnosis is based mainly on the appearance of the skin lesion, especially if there is a history of risk factors or related diseases.

Tests may include:

• Nikolsky's sign
• Skin lesion biopsy and microscopic examination of the tissue

Treatment goals include:

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

Stop taking any suspected medications, with your doctor's approval.

Treatment of mild symptoms may include:

• Medications such as antihistamines to control itching
• Moist compresses applied to the skin
• Over-the-counter medications (such as acetaminophen) to reduce fever and discomfort
• Topical anesthetics (especially for mouth lesions) to ease discomfort that interferes with eating and drinking

Treatment of severe symptoms may include:

• Antibiotics to control any skin infections
• Corticosteroids to control inflammation
• Hospitalization and 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

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

Skin grafting may be helpful in cases in which large areas of the body are affected.

In cases that are caused by the herpes virus, daily antiviral medications may be prescribed to prevent erythema multiforme from returning.

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

• 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)

Go to the emergency room or call the local emergency number (such as 911) if you have symptoms of erythema multiforme. If a large area of the body is involved, it is an emergency situation.

Lamoreux MR, Sternbach MR, Hsu WT. Erythema Multiforme. Am Fam Physician. 2006;74:1883-1888.

Erythema multiforme. In: Ferri FF. Ferri's Clinical Advisor. 1st ed. Philadelphia, Pa: Mosby Elsevier; 2009.