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Northeast Indiana Pediatric Specialists, PC |
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Dr. Michael Dick & Dr. Todd Dillon nips@med-web.com |
An inflammatory eruption characterized by symmetric erythematous,
edematous, or bullous lesions of
the skin or mucous membranes.
No cause of erythema multiforme can be found in > 50% of cases. Most other cases are due to infectious diseases (eg, herpes simplex
[probably most common], coxsackieviruses and echoviruses, Mycoplasma pneumoniae,
psittacosis, histoplasmosis) or drug therapy. Almost any drug can cause
erythema multiforme; penicillin, sulfonamides, and barbiturates are the
most likely. Vaccinia, bacille Calmette-Guérin (BCG), and poliomyelitis
vaccines have also induced erythema multiforme.
The mechanism by which
infectious agents, drugs, or vaccines cause erythema multiforme is unknown,
but it is generally considered a hypersensitivity reaction.
Onset is usually sudden, with
erythematous macules, papules, wheals, vesicles, and sometimes bullae
appearing mainly on the distal portion of the extremities (palms, soles)
and on the face; hemorrhagic lesions of the lips and oral mucosa can also
occur (see Oral Erythema Multiforme in Ch. 105). The skin lesions (target
or iris lesions) are symmetric in distribution and often annular, with
concentric rings, central purpura, and grayish discoloration of the
epidermis or vesicle. Itching is variable. Systemic symptoms vary; malaise,
arthralgia, and fever are frequent. Attacks sometimes last 2 to 4 wk and
recur in the fall and spring for several years.
Stevens-Johnson
syndrome is a
severe form of erythema multiforme (erythema multiforme major)
characterized by bullae on the oral mucosa, pharynx, anogenital region, and
conjunctiva; target-like lesions; and fever. The patient may be unable to
eat or properly close the mouth. Consultation with a dermatologist and
ophthalmologist is usually prudent. The eyes may become very painful;
purulent conjunctivitis may make it impossible for the patient to open
them. Symblepharon production, keratitis with corneal ulceration, iritis,
and uveitis may occur. The conjunctival lesions may leave resistant corneal
opacity and synechia. The condition is occasionally fatal.
The skin lesions of erythema
multiforme must be distinguished from bullous pemphigoid, urticaria, and
dermatitis herpetiformis; the oral lesions, from aphthous stomatitis,
pemphigus, and herpetic stomatitis. Hand, foot, and mouth disease produced
by coxsackieviruses A5, A10, and A16 must also be considered.
The cause, if found, should be
treated, eliminated, or avoided. Simple erythema often needs no treatment.
Erythema multiforme associated with mycoplasmal pneumonia should be treated
with tetracycline. Local treatment depends on the type of lesion. Vesicles
and bullous or erosive lesions can be treated with intermittent Burow's
solution, saline, or tap-water compresses. Cheilitis and stomatitis of
erythema multiforme may require special care (see Oral Erythema Multiforme
in Ch. 105). Use of systemic corticosteroids (see Drug Eruptions, above) is
controversial; some patients, especially those with severe mouth and throat
lesions, seem to succumb more readily to fatal respiratory infections if
treated with systemic corticosteroids. However, these drugs have been
beneficial in severe erythema multiforme (if used early) and in chronic
erythema multiforme. Systemic antibiotics (as indicated by culture and
sensitivity) and fluid and electrolyte replacement may be lifesaving in
patients with extensive mucous membrane lesions. If frequent or severe
erythema multiforme is preceded by herpes simplex, acyclovir 200 mg po
three or five times daily may prevent attacks.