What is Erythema multiforme?
Erythema multiforme is a sudden (acute) inflammation of the skin.
It can also affect the thin moist tissue lining the body's cavities (internal mucous membranes).
Although half of all cases occur for no apparent reason, erythema can also occur as a reaction to certain medications.
Other causes include viral infections (such as cold sores), bacterial infections (such as mycoplasma pneumonia), pregnancy, vaccination, or radiation therapy.
Erythema multiforme is most common in children and young women.
There are two forms of severe erythema multiforme: Stevens-Johnson disease and toxic epidermal necrolysis. In Stevens-Johnson, the mucous membranes of the lips, mouth, eyes, nasal passages, and genitals can blister and bleed. In toxic epidermal necrolysis, the mucous membrane bleeding is less severe.
Erythema multiforme signs and symptoms
- Rash spots that are red and symmetrical in shape, frequently appearing as concentric rings like bull's-eyes.
- Rash usually appears on palms, soles, other areas of arms and legs, may spread to face and rest of the body.
- Rash is itchy, sometimes painful or has burning sensation.
- Rash develops into blisters, hives, or becomes ulcerated.
- In the major form, the mucous membranes of the mouth, eyes, and genitals become inflamed.
- Sore throat.
How is it diagnosed?
History: The individual may complain of a rash beginning on arms or legs and spreading to the face and rest of the body. Rash may or may not be itchy. A fever, sore throat, headache, or diarrhea can accompany the rash.
Physical exam: The red rash may appear in separate rings, bull's-eye (concentric) rings, or disk-shaped patches. It may progress to raised, pale-centered wheals (hives) or blisters. In Stevens-Johnson syndrome, the mucous membranes of the lips, mouth, eyes, nasal passages, and genitals become inflamed and ulcerated.
Tests include skin biopsy with immunofluorescence examination and culture (or rapid test) to rule out bacterial or viral infection.
How is it treated?
If caused by a reaction to medication, the medication can be changed or discontinued. A bacterial infection is treated with antibiotics. Antiviral medications can lessen symptoms of viral infections. Anti-inflammatory medications (corticosteroid) lessen inflammation and irritation. Protection from factors that might precipitate the condition and wet compresses for the exudative lesions are used. The severe forms may require painkillers, sedatives, and corticosteroids to reduce inflammation. In rare instances, plasma exchange may be used.
- Corticosteroids may be prescribed to reduce inflammation and irritation.
- Acyclovir may be prescribed to treat viral infection such as herpes simplex virus.
- Antibacterial medications, if secondary infection present.
- If mouth sores are present, topical medications or mouthwashes may be prescribed.
- If eyes are involved, eyewashes or other topical medications may be prescribed.
- Pain medications, sedatives, or antihistamines may be prescribed to help provide relief of symptoms.
- Usually no special diet is necessary.
- If mouth sores are present, a soft or liquid diet may be better tolerated.
- Increased fluid intake sometimes helpful.
- Intravenous fluids may be required in hospitalized patient.
What might complicate it?
With Stevens-Johnson syndrome, the individual may become seriously ill due to the inflammation spreading within the body. There is also the risk of going into shock. Keratitis, visual impairment, and pneumonia occur in 30% of individuals.
Although it can recur, erythema multiforme is usually gone within five to six weeks. Individuals with recurrent disease usually have long periods without disease.
Other possibilities include urticaria and erythema nodosum.
Last updated 3 April 2018