Erythema Multiforme

Erythema multiforme is a skin reaction that creates distinctive target-shaped marks on your body, usually triggered by infections or medications. While the rash can be uncomfortable and alarming, most cases resolve on their own within a few weeks.

Table of contents

• What is erythema multiforme?
• Types of erythema multiforme
• Who is affected
• Symptoms and appearance
• Causes and triggers
• Diagnosis
• Treatment and management
• Outlook and recovery

What is erythema multiforme?

Erythema multiforme is a skin condition where your body reacts to an infection or medication by developing a rash. The name comes from the fact that the condition takes multiple forms on your skin, appearing as flat spots, raised bumps, or blisters^[1]. These skin changes, called lesions, can appear suddenly and may affect different parts of your body.

The condition is an immune-mediated reaction, which means your body’s defense system responds to something it perceives as a threat, causing changes in your skin and sometimes in the moist tissues of your body^[6]. The exact process isn’t fully understood, but research shows that increased blood flow to certain small blood vessels near the skin’s surface causes the characteristic redness and swelling^[2].

Erythema multiforme is now recognized as separate from more serious conditions like Stevens-Johnson syndrome and toxic epidermal necrolysis, even though they were once thought to be related^[6].

Types of erythema multiforme

There are two main types of erythema multiforme, which differ in severity and the areas of the body they affect^[1].

Erythema multiforme minor is the milder form. It mainly affects your skin and causes a rash. People with this type are unlikely to have symptoms in their mucous membranes (the moist linings of the mouth, eyes, and genitals) or general symptoms like fever or chills^[1].

Erythema multiforme major is the more severe form and can potentially be life-threatening. This type causes large areas of skin to develop blisters and peel. It affects the mucous membranes in the mouth, eyes, and genitals. People with this form usually experience body-wide symptoms such as fever or joint pain^[1].

Who is affected

Erythema multiforme is a rare condition, affecting less than 1% of all people^[12]. It can happen to anyone, but it’s most common in children, young adults, and people under 40 years old^[1]. The condition occurs about five times more often in males than females^[12]. About 20% of cases occur in children^[12].

Symptoms and appearance

The main symptom of erythema multiforme is a rash that usually appears on your hands and feet first, then spreads to your stomach, chest, back, or face^[3]. Most lesions develop within 48 to 72 hours^[6]. The rash might feel itchy or like it’s burning^[3].

The rash typically starts as round, slightly raised spots. Some spots develop rings around them and can turn into blisters^[3]. The most characteristic feature is a round mark on your skin that looks like a bulls-eye or target, with a dark center and a pale ring around it^[1]. Depending on your skin tone, the rash may appear red, pink, purple, or darker than the surrounding skin^[3].

Skin symptoms can include^[1]:

• A red to purple rash that causes swelling and is painful to touch
• Pimple-like blisters on your skin or inside your mouth
• Itchy skin

Sometimes the rash can appear inside your mouth, on your lips, eyes, bottom, or genitals, which can be painful^[3]. When the condition affects these areas, you might have difficulty eating, drinking, urinating, or seeing^[1].

Other symptoms may include^[1]:

• Headache
• Feeling tired
• Fever
• Joint pain and soreness
• Eye sensitivity, blurred vision, sore or red eyes
• Feeling generally unwell

The skin symptoms usually go away after two to four weeks^[1]. The rash generally remains in one location and heals within 7 to 21 days^[6].

Causes and triggers

The exact cause of erythema multiforme isn’t fully understood, but research shows it’s most often triggered by infections^[1]. Infections are associated with 90% of cases^[8].

The most common trigger is herpes simplex virus (HSV), particularly type 1, though type 2 can also cause the condition^[8]. This is the same virus that causes cold sores^[3]. The second most common cause is Mycoplasma pneumoniae, a bacteria that causes lung infections like pneumonia, especially in children^[8].

Other infections that can trigger erythema multiforme include^[8]:

• Cytomegalovirus
• Epstein-Barr virus
• Hepatitis C virus
• Influenza virus

Medications cause less than 10% of cases^[8]. When medications are the trigger, they can include^[1]:

• Antiseizure medications
• Antibiotics (including penicillins, sulfonamides, erythromycin, nitrofurantoin, and tetracyclines)
• Nonsteroidal anti-inflammatory drugs (NSAIDs)
• Barbiturates
• Statins

Other possible triggers include certain vaccines (such as measles, mumps, rubella, smallpox, hepatitis B, meningococcal, pneumococcal, varicella, influenza, and Haemophilus influenzae), though these are rare^[8]. Less commonly, autoimmune conditions and inflammatory bowel disease have been linked to erythema multiforme^[8].

Erythema multiforme itself is not contagious. The lesions, blisters, or rash cannot spread from person to person. However, if a virus or bacteria caused your symptoms, that infection can spread to others, though they might not develop erythema multiforme^[1].

Diagnosis

Your doctor may suspect erythema multiforme when they examine your skin, particularly if they see the characteristic target-shaped lesions^[12]. To confirm the diagnosis and rule out other conditions, several tests may be performed.

Blood tests may check your complete blood cell count. Signs of erythema multiforme can include high levels of white blood cells and mild anemia. Your doctor might also check your erythrocyte sedimentation rate, which measures how fast red blood cells sink in a test tube. An elevated rate could indicate erythema multiforme^[12].

A skin biopsy involves examining your skin closely under a microscope to look for characteristic changes that occur with erythema multiforme^[12].

A chest X-ray may be done to look for signs of bacterial infection such as pneumonia^[12].

Your doctor may also check for potential triggers, including looking for skin lesions that might indicate a herpes simplex virus infection or symptoms like a cough that might suggest pneumonia^[12].

Treatment and management

Most cases of erythema multiforme get better on their own within 2 to 4 weeks^[3]. Mild cases require only symptom relief^[9].

For managing symptoms at home, you may use^[9]:

• Pain relievers or NSAIDs to control pain and discomfort
• Cold compresses with saline or Burrow solution
• Topical steroid creams to speed recovery and ease itching
• Antihistamines for itching

For mouth involvement, soothing treatments like saline gargles, viscous lidocaine, or diphenhydramine elixir may help^[9]. Oral anesthetics can decrease pain from oral lesions^[8].

If an infection is causing your symptoms, treating that infection is important^[3]. This might include antiviral medicine if a virus is responsible. However, starting antiviral treatment after the erythema multiforme rash has already appeared has no effect on the course of the condition^[9].

If a medication triggered your symptoms, you’ll usually need to stop taking it, but never stop any medicine without talking to your doctor first^[3]. The medication must be withdrawn as soon as possible if it’s suspected^[9].

For severe cases of erythema multiforme major, hospitalization may be necessary. Treatment in hospital focuses on^[9]:

• Aggressive monitoring and replacement of fluids and electrolytes
• Supportive respiratory care including suctioning and postural drainage if needed
• Intravenous fluids and electrolyte replacement

For eye involvement, urgent consultation with an eye specialist is recommended^[8]. Local care includes topical lubricants for dry eyes, sweeping of the eye folds, and removal of fresh adhesions^[9].

If you have recurrent erythema multiforme caused by herpes simplex virus (more than five attacks per year), preventive antiviral therapy should be considered^[9]. Oral acyclovir at a dose of 200 mg once daily to 400 mg twice daily can be effective. In children, 10 mg per kg per day may be considered. Prevention may be required for 6 to 12 months or longer^[9]. If unresponsive, continuous therapy with valacyclovir (500 mg twice daily) or famciclovir (250 mg twice daily) has been reported to be effective^[9].

Outlook and recovery

Erythema multiforme is generally a self-limiting condition that resolves without significant complications^[6]. Most cases heal completely within two to four weeks^[1].

While the condition usually causes a painful or uncomfortable rash, treatment helps alleviate symptoms and get you feeling better^[1]. Only a limited number of cases become persistent^[6]. Recurrences are not uncommon if the trigger is herpes simplex virus^[6].

The mucous membranes are involved in 2% to 10% of cases^[6]. When erythema multiforme is severe and affects the mouth and eyes, symptoms can make it difficult to eat, drink, and see. Depending on the severity, hospital treatment may be needed^[1].