Erythema multiforme is a rare skin condition that is typically caused by an infection or medicinal allergy. The self-limited, acute and sometimes recurring condition is recognized as a hypersensitivity reaction to various triggers including some drugs like nonsteroidal anti-inflammatory medications, anticonvulsants, and antibiotics, along with infections, especially HSV (herpes simplex virus). Some individuals experience mild forms of the condition while others develop severe cases. The condition often presents itself as a target lesion skin eruption where the mucous membrane is often involved.
This condition was once listed in the same category as TEN (toxic epidermal necrolysis) and SJS (Stevens-Johnson syndrome). However, it is now been separated into minor and major category forms of its own condition that is separated from the more serious forms TEN and SJS.
- Who Is at Risk for Erythema Multiforme?
- Common Symptoms
- Diagnosing Erythema Multiforme
- Treating the Condition
Who Is at Risk for Erythema Multiforme?
Because the condition is caused by an allergic reaction, any individual is at risk for developing erythema multiforme. In rare cases, it can be triggered by a systemic (body wide) illness or specific medicines. Individuals who are most at risk are those that are exposed to certain infections, medicines and systemic illnesses including:
- Bacterial infections including lung infections caused by mycoplasma pneumonia
- Viruses including genital herpes and herpes simplex that produce cold source
- Fungus is that causes histoplasmosis by the Histoplasma capsulatum fungus
- NSAIDs – nonsteroidal anti-inflammatory drug like ibuprofen
- Specific antibiotics including formulated with aminopenicillin and sulfonamide
- Anti-seizure medications
- Medications that treat gout (allopurinol)
- Sufferers of Crohn's disease and other inflammatory bowel diseases
- Suffeerrs of systemic lupus erythematosus
- Those who have received vaccinations for polio, tetanus, diphtheria, and BCG (Bacille Calmette-Guerin)
The age of the patient is a factor, where most individuals who suffer from erythema multiforme are between 20 and 40 years of age. In addition, a family history of the disease can also increase the potential risk of someone developing the condition. Infection-induced erythema multiforme is more common in children.
Less common risk factors of erythema multiforme involve:
- Exposure to preservatives and flavoring including cinnamon and benzoic acid
- Exposure to foods including margarine and salmon berries
- Mechanical and physical factors including exposure to sunlight, cold, radiotherapy, chemotherapy, and tattooing
- Immunologic disorders including collagen diseases, leukemia, non-Hodgkin lymphoma, myeloid metaplasia, multiple myeloma, polycythemia, sarcoidosis, vasculitis, and transient selective C4 deficiency of infancy
- Changes in hormones
The most common symptoms associated with erythema multiforme involve:
- Overall ill feeling
- Achy joints
- Itchy skin
- Numerous skin lesions appearing in abnormal areas
- Quickly developing skin sores that easily spread, appear like hives, are discolored, raisde, recurring, or appear as a bulls-eye (target) with pale red rings surrounding a central sore
- Blisters and bumps filled with liquid
- Many sores that appear on the lips or face or are located on the feet, hands, palms, arms, legs, and upper body
- Symmetrical appearing sores that appear on both legs, both arms, or both sides of the body
Usually, erythema multiforme will develop just as a mouth sore or a skin sore before the condition worsens. Major cases of erythema multiforme usually begin as an achy joint or high fever before developing into a mouth or skin sore that can also develop in the gut, lung airways, genitals and eyeballs.
Diagnosing Erythema Multiforme
Verifying a case of erythema multiforme requires a clinical diagnosis that might include a skin biopsy to ensure other conditions are excluded or ruled out. While the histology of the condition is highly characteristic, it is not easy to diagnose without a biopsy of the lesion. Often, the lesion appears as a mycoplasma infection or other condition that shares the same mechanisms and histology.
The doctor will need to complete a comprehensive personal history to determine all the medicines the patient has taken in recent years along with any infection they may have acquired. Medical history will help the doctor understand the condition is recurring or not before recommending an effective treatment that could include "watchful waiting." This means the doctor takes a wait-and-see attitude to determine if the condition worsens over time and causes significant symptoms that require relief.
The doctor may recommend a differential diagnosis when the condition is its initial stages to determine if the lesions are caused by drugs, polymorphic light, viruses, bacteria, or other hypersensitivity reaction. The doctor must rule out urticaria because it so closely resembles erythema multiforme during the onset of a typical skin irruption. The doctor must distinguish the subtle clinical features of the condition to rule out other diseases.
That said, urticaria-related lesions usually do not appear longer than 24 hours at the affected site and typically have more defined borders compared to erythema multiforme. The doctor can verify or rule out lupus erythematosus, pityriasis rosea, figurate erythema, or vasculitis that develop lesions that tend to appear with subcutaneous bleeding or dusty centers. If the lesion appears to be bullous (like a blister) the condition must be distinguished from similarly appearing autoimmune bullous diseases.
Treating the Condition
The only successful way to treat erythema multiforme is to determine if it is caused by an allergy, or what is causing the problem. If the doctor can determine a causal medication, exposure to infection, or link of previous condition or recurrence to the condition, developing and implementing a treatment plan can be highly effective.
In many instances, the patient will not require any treatment at all. The doctor may recommend that the patient uses intermittent moist compresses on erosive and blistering lesions to alleviate itching or use topical anesthetics in the mouth and on the lips to manage many of the associated symptoms of mouth and lip sores.
Other times, the doctor will likely recommend a topical steroid or oral antihistamine to provide relief to many of the associated symptoms including itchy skin and achy joints. If the doctor determines that a viral infection caused the condition, they will likely recommend oral Zovirax (acyclovir) that often lessens the duration and number of cutaneous lesions. While this medication is proven to be highly effective, it is best to start the treatment within the first few days after an outbreak.
Other patients will be prescribed prednisone at high doses for up to two weeks. However, this recommended treatment remains highly controversial because no controlled studies have been performed to verify the effectiveness of prednisone use. Taking prednisone can be highly dangerous, especially if the patient suffers severe throat and mouth sores. This is because it can easily lead to fatal respiratory infections. It is highly recommended to seek immediate medical attention if the prednisone prescription is not producing the desired outcome in the patient is developing severe side effects.
Alternatively, individual suffering recurrent erythema multiforme often receive a recommendation of following the suppressive antiviral therapy performed by a competent dermatologist. The prognosis (Outlook) for many patients who suffer minor cases of erythema multiforme is good, where the condition will become significantly better in as little as two to six weeks. However, many individuals suffer from recurring episodes of the condition or develop potential complications including patchy skin color and a return of erythema multiforme during an outbreak of a viral infection.