Erythema multiforme

Alternative names:

Stevens-Johnson syndrome; toxic epidermal necrolysis; Lyell'ssyndrome

Definition:

A skin disorder resulting from an allergic reaction.

Causes, incidence, and risk factors:

Erythema multiforme is a type of hypersensitivity (allergic)reaction that occurs in response to medications, infections, or illness.Medications associated with erythema multiforme include sulfonamides,penicillins, barbiturates, and phenytoin. Associated infections includeherpes simplex and mycoplasma infections.

The exact cause is unknown. The disorder is believed toinvolve damage to the blood vessels of the skin with subsequent damage toskin tissues. Approximately 90% of erythema multiforme cases are associatedwith herpes simplex or Mycoplasma infections. The disorder occurs primarilyin children and young adults.

Erythema multiforme may present with a classic skin lesionwith or without systemic (whole body) symptoms. In Stevens-Johnson syndrome,the systemic symptoms are severe and the lesions are extensive, involvingmultiple body areas (especially the mucous membranes). Toxic epidermalnecrolysis (TEN syndrome, or Lyell's syndrome) involves multiple large blisters(bullae) that coalesce, followed by sloughing of all or most of theskin and mucous membranes.

Prevention:

No prevention is known. Avoidance of known allergens (substancesthat cause allergic reaction) may reduce the risk.

Symptoms:

* skin lesion

_o multiple

_o with sudden onset, may recur

_o may spread

_o may appear as nodule, papule, or macule

_o central lesion surrounded by concentric ringsof pallor and redness ("target", "iris", "bull's eye"shape)

_o may have vesicles and bullae (blisters of varioussizes)

_o located on the legs, arms, palms, hands, orfeet

_o may involve the face and/or lips

_o trunk is usually not involved

_o usually symmetrical

* itching of the skin may be present

* fever

* general ill feeling (malaise)

* joint aches

Additional symptoms that may be associated with thisdisease:

* vision abnormalities

* tearing, decreased

* mouth sores

* eyes, bloodshot

* eye pain

* eye burning, itching and discharge

Signs and tests:

* positive Nikolsky's sign

The diagnosis is primarily based on the classic skin lesionappearance and typical symmetrical distribution, especially if there isa history of risk factors or associated diseases.

A skin lesion biopsy and microscopic examination may behelpful to differentiate erythema multiforme from other disorders.Erythema multiforme may show keratinocyte necrosis (tissue death) and otherchanges. Microscopic examination of the tissue may also show deposits of immunecomplexes(antibody deposits).

Treatment:

Treatment goals include control of the underlying causesor illnesses, treatment of the symptoms, and prevention of infection.Suspected medications should be discontinued.

Treatment of mild symptoms may include:

* moist compresses applied to skin lesions

* medications such as antihistamines to controlitching.

* over-the-counter medications such as acetaminophento 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:

* hospitalization and treatment in an intensive careor burn care unit for severe cases, Stevens-Johnson syndrome, and toxicepidermal necrolysis

* systemic corticosteroids to control inflammation

* antibiotics to control secondary skin infections

Good hygiene and isolation from others may be required toprevent secondary infections.

Extensive skin involvement may cause the loss of largequantities of body fluids, causing shock in addition to the risk of infection.Intensive care with support of body systems may be required.

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

Expectations (prognosis):

Mild forms of erythema multiforme usually resolve withoutdifficulty in 2 to 6 weeks but may recur. More severe forms may be difficultto treat. Stevens-Johnson syndrome and toxic epidermal necrolysisare associated with high death rates.

Complications:

* permanent skin damage and scarring

* occasionally, lesions on internal organs causing:

_o pneumonitis

_o myocarditis

_o nephritis

* a secondary skin infection (cellulitis)

* systemic infection, sepsis

* the loss of body fluids, shock

Calling your health care provider:

Go to the emergency room or call the local emergency number(such as 911) if symptoms indicate erythema multiforme. Involvement of alarge area of the body is an emergency situation.

Dr. Song's Oral Medicine Forum