Erythema multiforme is a skin condition that appears when your body reacts to an infection or medication, creating distinctive red, target-shaped marks on the skin that can be itchy and painful, though the condition usually resolves on its own within a few weeks.
Understanding Erythema Multiforme
Erythema multiforme is an immune-mediated skin reaction that affects both the skin and sometimes the mucous membranes. The name itself provides insight into the condition: “erythema” comes from the Greek word “erythros,” meaning red, while “multiforme” refers to the multiple forms the condition can take on your skin—ranging from flat spots to raised bumps or blisters. This reaction is typically triggered by the body’s immune response to an infection or, less commonly, to a medication.
The condition gets its distinctive appearance from the way it manifests. Most characteristically, it produces circular marks on the skin that look remarkably like a target or bulls-eye, with a dark center surrounded by a lighter ring, all encircled by a red outer ring. These lesions can appear suddenly and may come and go unexpectedly, affecting various parts of the body including the hands, feet, trunk, and sometimes the eyes, mouth, and genitals.
There are two main forms of this condition. Erythema multiforme minor is the milder version that primarily affects the skin and causes a rash, typically without involvement of the mucous membranes like the mouth or eyes, and without systemic symptoms such as fever or chills. Erythema multiforme major, on the other hand, is more severe and can be life-threatening because it causes large areas of skin to blister and peel. This form affects the mucous membranes in the mouth, eyes, and genitals, and people with this type usually experience systemic symptoms such as fever and joint pain.
Who Gets Erythema Multiforme
Erythema multiforme is considered a rare condition, affecting less than 1% of the population. While it can affect anyone at any age, it shows a clear pattern in who it most commonly affects. The condition is most frequently seen in children, young adults, and people under the age of 40. Among those affected, it appears to be about five times more common in males than females, though the reasons for this gender difference are not fully understood.
Approximately 20% of cases occur in children. Most cases in adults tend to appear in people in their 20s and 30s. There is no apparent association with race, meaning people of all ethnic backgrounds can develop the condition equally.
What Causes This Skin Reaction
The exact cause of erythema multiforme is not completely understood, but research has identified several key triggers. The condition develops through a cell-mediated immune response, which is a type of immune reaction where specific immune cells attack what they perceive as threats. About 90% of cases are associated with infections, making them the most common trigger by far.
The herpes simplex virus (HSV) stands out as the most frequently identified cause. Both HSV type 1, which typically causes cold sores, and HSV type 2 can trigger erythema multiforme. When the condition is related to herpes, it’s called herpes-associated erythema multiforme, and it can recur whenever the virus reactivates in the body. The second most common infectious trigger is Mycoplasma pneumoniae, a bacteria that causes lung conditions like pneumonia, particularly in children.
Other viral infections that can trigger the condition include cytomegalovirus, Epstein-Barr virus, hepatitis C virus, and influenza virus. Even vulvovaginal candidiasis, a fungal infection, has been linked to cases of erythema multiforme.
Medications cause less than 10% of erythema multiforme cases, making them a less common trigger than infections. However, many different drugs have been associated with the condition. Antibiotics are among the most common medication triggers, including sulfonamides, penicillins, erythromycin, nitrofurantoin, and tetracyclines. Other medications that may trigger the condition include antiseizure medications, nonsteroidal anti-inflammatory drugs (NSAIDs)—which are common pain relievers—barbiturates, phenothiazines, statins used to lower cholesterol, and tumor necrosis factor-alpha inhibitors used to treat autoimmune conditions.
Vaccines have also been associated with erythema multiforme, though the incidence is quite low. Vaccines that have been linked to cases include measles, mumps, and rubella; smallpox; hepatitis B; meningococcal; pneumococcal; varicella; influenza; and Haemophilus influenzae vaccines, as well as COVID-19 vaccines.
Less commonly, erythema multiforme has been associated with autoimmune disorders, inflammatory bowel disease, malignancy, and even menstruation in some individuals.
Recognizing the Symptoms
The symptoms of erythema multiforme can appear suddenly, often within 48 to 72 hours, without any prior warning. Most commonly, lesions appear in a fixed location and remain for about 7 to 21 days before healing. The primary symptom is a distinctive rash with very specific characteristics.
The rash typically begins on the hands and feet, particularly on the extensor surfaces (the backs of the hands and tops of the feet), and then spreads centrally toward the trunk, chest, back, or face over the following days. The rash usually starts as round, slightly raised spots that may feel itchy or like they’re burning. These spots can develop rings around them and may turn into blisters. The classic appearance is the target or bulls-eye lesion—a round mark on the skin with a dark center and a pale ring around it, all surrounded by a red outer ring.
Depending on your skin tone, the appearance can vary. In people with fair skin, the rash may appear red or pink. On darker skin tones, it may look violet, purple, or darker than the surrounding skin. This is important to recognize because the term “redness” can be misleading—the color change in erythema can run the spectrum from pink to red to purple, and in some cases may be limited to a subtle darkening of the existing skin color.
The skin symptoms are often accompanied by other physical signs. The affected areas may feel warm to the touch and may swell slightly. The skin can become painful to touch, and many people experience itching. Some people develop pimple-like blisters on their skin or inside their mouth.
Beyond the skin, other symptoms can include headache, feeling extremely tired (fatigue), fever, joint pain and soreness, and muscle stiffness. When the eyes are involved, symptoms may include eye sensitivity to light, blurred vision, sore eyes, red eyes, eye pain, itching, or burning sensations. In cases where the rash appears inside the mouth or on the lips, eyes, anus, or genitals—which is more common in erythema multiforme major—the lesions can be painful and may interfere with eating, drinking, urinating, or seeing clearly.
The symptoms that affect the skin usually resolve on their own after two to four weeks. Most lesions remain localized to one site and heal within this timeframe. However, in some cases, symptoms may go away and then come back a few months later, particularly if the underlying trigger (such as herpes simplex virus) reactivates.
When to Seek Medical Care
While many cases of erythema multiforme are mild and resolve without complications, there are certain situations where medical attention is necessary. You should see a doctor if you develop symptoms of erythema multiforme or if the condition keeps coming back, as it may be possible to treat the underlying cause.
Urgent medical attention is needed if the rash appears inside your mouth or on your lips, eyes, anus, or genitals, or if the rash is painful and you’re finding it difficult to eat or urinate. You should also seek urgent care if you develop a high temperature or body aches and pains, or if the rash appeared after you started taking a new medicine.
How Doctors Diagnose the Condition
Diagnosis of erythema multiforme typically begins with a physical examination. Your doctor may suspect the condition based on the characteristic appearance of the target-like lesions on your skin. However, to confirm the diagnosis and rule out other conditions, additional tests may be necessary.
Your doctor will look closely at your skin to identify the distinctive features of erythema multiforme, particularly the target or iris lesion characterized by three concentric segments: a dark center, surrounded by a lighter pink ring, both of which are surrounded by a red ring. They will also assess where on your body the lesions appear and whether your mucous membranes are involved.
Blood tests may be ordered to check your complete blood cell count. Signs of erythema multiforme can include high levels of white blood cells and mild anemia. Your doctor may also check your erythrocyte sedimentation rate, which measures how fast red blood cells sink to the bottom of a test tube—if it’s elevated, it could indicate erythema multiforme.
A skin biopsy might be performed, where your doctor takes a small sample of affected skin to examine closely under a microscope. This can help identify the specific changes in skin tissue that are characteristic of erythema multiforme and differentiate it from other similar-looking conditions.
A chest X-ray may be taken to look for signs of a bacterial infection, such as pneumonia, which could be triggering the condition. Your doctor may also check for potential triggers by looking for skin lesions that could indicate a herpes simplex virus infection, or by checking for symptoms such as a cough that might suggest pneumonia.
Treatment and Management
The good news is that erythema multiforme usually gets better on its own within 2 to 4 weeks without requiring extensive treatment. The main focus of treatment is on managing symptoms, treating any underlying infection or trigger, and providing supportive care to help you feel more comfortable during the healing process.
For mild cases of erythema multiforme, symptomatic treatment is typically sufficient. This may include cold compresses with saline or Burrow solution applied to the affected areas, moisturizers or topical steroid creams to speed up recovery and help ease symptoms like itching, and oral antihistamines to reduce itching and discomfort. Analgesics—pain relief medications—should be administered as needed to control pain, which may be severe in some cases.
If the rash is inside your mouth, oral anesthetics such as viscous lidocaine or diphenhydramine elixir may be helpful in decreasing the pain of oral lesions. Soothing oral treatments like saline gargles can also provide relief. If you have ocular involvement, artificial wetting solutions or antibiotic ointments may be helpful, and urgent ophthalmologic consultation is recommended for any eye involvement.
When an infection is identified as the trigger, appropriate treatment for that infection is essential. For viral infections, antiviral medicine may be prescribed. For bacterial infections like Mycoplasma pneumoniae, antibiotics would be appropriate. If a medication is suspected to be the cause, it must be withdrawn as soon as possible—this includes all medications begun during the preceding 2 months. However, it’s crucial not to stop taking any medicines without talking to a doctor first, as suddenly stopping some medications can be dangerous.
In severe cases of erythema multiforme major, hospitalization may be necessary. Aggressive monitoring and replacement of fluids and electrolytes become paramount, particularly if the person is having difficulty eating or drinking due to painful oral lesions. Supportive respiratory care, including suctioning and postural drainage, should be provided as necessary. The use of liquid antiseptics during bathing helps prevent superinfection of the damaged skin.
For recurrent erythema multiforme, particularly when it’s associated with herpes simplex virus, prophylactic (preventive) antiviral therapy is recommended. Continuous prophylactic antiviral treatment has been shown to be effective for recurrent herpes-associated erythema multiforme. Oral acyclovir in a dosage of 200 mg once daily to 400 mg twice daily can be effective, even in subclinical herpes simplex virus infection. In children, 10 mg/kg/day may be considered. If the condition is unresponsive to acyclovir, continuous therapy with valacyclovir (500 mg twice daily) or famciclovir (250 mg twice daily) has been reported to be effective. Prophylaxis may be required for 6 to 12 months or longer, and should be considered in patients with more than five attacks per year.
The use of systemic corticosteroid therapy remains controversial in erythema multiforme. Some believe it may predispose to complications, while others use it in severe cases. If given, the course should be limited to 10 to 14 days.
Prevention Strategies
While it’s not always possible to prevent erythema multiforme, there are several strategies that can help reduce your risk or prevent recurrences. The most important step is identifying and avoiding known triggers. If you’ve had erythema multiforme before, working with your doctor to identify what triggered it can help you avoid that trigger in the future.
For people who experience recurrent erythema multiforme associated with herpes simplex virus, taking preventive antiviral medication as prescribed by your doctor can significantly reduce the frequency of episodes. This prophylactic treatment works even when there are no visible signs of a herpes outbreak.
Basic education on avoiding triggers has been shown to be effective. For instance, sun exposure is a known trigger for various skin conditions, and protecting your skin from the sun with broad-spectrum sunscreen, protective clothing, and hats can be helpful. If certain medications have triggered erythema multiforme for you in the past, make sure all your healthcare providers know about this so they can avoid prescribing those medications or similar ones.
Maintaining good overall health and a strong immune system can also be beneficial. This includes getting adequate sleep, managing stress, eating a balanced diet, and keeping any chronic conditions well-controlled. If you have a condition that increases your risk of infections, such as a weakened immune system, taking steps to prevent infections can indirectly help prevent erythema multiforme.
How the Condition Affects Your Body
Understanding what happens in your body during erythema multiforme can help you appreciate why the symptoms occur and how treatments work. The condition is fundamentally an immune-mediated hypersensitivity reaction, meaning your immune system overreacts to a perceived threat, even after that threat may no longer be present.
Erythema, the redness that gives the condition its name, occurs when blood vessels close to the skin’s surface dilate or expand. This is a change in color of an area of skin caused by increased blood flow in certain capillaries, the tiny blood vessels near the surface. When your body faces an injury, infection, or irritant, it increases blood flow to the affected area as part of the inflammatory response. This increased blood flow brings oxygen, nutrients, and immune cells to help deal with the problem, but it also causes the visible redness and can lead to swelling, heat, and pain in the affected area.
In erythema multiforme, the immune response involves both cellular and antibody-mediated mechanisms. Studies have shown that lesions associated with herpes simplex virus test positive for interferon-gamma, while drug-associated lesions have tested positive for tumor necrosis factor-alpha. These are signaling molecules that coordinate the immune response, but in this case, they contribute to the skin damage.
The characteristic target lesions form due to the way the immune response affects different layers and areas of the skin. The center of the target may show more severe damage, including cell death, while the surrounding rings represent different intensities of inflammation and blood vessel changes. When blisters form, it’s because the immune response has caused separation between layers of the skin, allowing fluid to accumulate.
In cases where mucous membranes are affected, the same inflammatory process damages these delicate tissues. The mucous membranes in the mouth, eyes, and genitals are more sensitive than regular skin, which is why involvement of these areas can be particularly painful and why erythema multiforme major is considered more serious.
The self-limiting nature of the condition—the fact that it typically resolves on its own—reflects that once the triggering infection is controlled or the offending medication is cleared from the body, the immune system gradually settles down and the inflammatory response subsides. The skin then heals naturally, though in some cases, temporary discoloration may remain for a period after the active lesions have resolved.
