Summary about Disease
Erythema multiforme (EM) is an uncommon skin condition characterized by distinctive, target-like lesions that appear suddenly. It is often a reaction to an infection, most commonly the herpes simplex virus (HSV), or certain medications. The condition is generally self-limiting, resolving on its own, but recurring episodes are possible, especially if triggered by recurrent HSV infections. In severe cases, it can involve the mucous membranes of the mouth, eyes, and genitals.
Symptoms
Target Lesions: The hallmark of EM is the appearance of target-shaped skin lesions. These lesions typically have three distinct zones: a central dark area (may be a blister or crust), a surrounding pale ring, and an outer red ring.
Location: Lesions are commonly found on the extremities (hands, feet, arms, legs), but can also appear on the face and trunk.
Symmetrical Distribution: The rash often appears symmetrically on both sides of the body.
Itching: The lesions may be itchy or cause a burning sensation.
Mucous Membrane Involvement (in some cases): Ulcers or blisters may form in the mouth, eyes, or genitals, causing pain and difficulty eating or urinating.
Fever and Malaise (in some cases): Systemic symptoms like fever, fatigue, and general discomfort may occur, particularly in more severe cases.
Causes
Herpes Simplex Virus (HSV): The most common cause of EM is infection with HSV-1 (oral herpes) or HSV-2 (genital herpes).
Medications: Certain medications, including antibiotics (sulfonamides, penicillins), anticonvulsants, and NSAIDs, can trigger EM.
Other Infections: Other infections, such as Mycoplasma pneumoniae, can also be associated with EM.
Vaccinations: In rare cases, vaccinations have been linked to EM.
Idiopathic: In some cases, the cause of EM cannot be identified.
Medicine Used
Antiviral Medications: If HSV is the trigger, antiviral medications like acyclovir, valacyclovir, or famciclovir may be prescribed to suppress the virus.
Antihistamines: To relieve itching.
Pain Relievers: Over-the-counter or prescription pain relievers may be used to manage pain associated with mouth ulcers or other symptoms.
Topical Corticosteroids: To reduce inflammation and itching of the skin lesions.
Oral Corticosteroids (in severe cases): In severe cases, oral corticosteroids may be prescribed to reduce inflammation throughout the body.
Mouthwashes/Topical Anesthetics: For oral lesions, mouthwashes containing anesthetics or corticosteroids may be used to relieve pain and promote healing.
Is Communicable
Erythema multiforme itself is not communicable. It is a reaction to an underlying trigger, not a contagious disease. However, if the trigger is a communicable infection like herpes simplex virus, that infection can be spread to others.
Precautions
Identify and Avoid Triggers: If a medication is identified as the trigger, it should be discontinued under the guidance of a doctor.
Manage HSV Infections: If HSV is the trigger, taking antiviral medication can reduce the frequency and severity of outbreaks.
Good Hygiene: Keeping the affected areas clean and dry can help prevent secondary infections.
Avoid Irritants: Avoid harsh soaps, detergents, and other irritants that may worsen the skin condition.
Eye Care (if applicable): If the eyes are affected, consult an ophthalmologist and follow their recommendations for eye care, which may include lubricating eye drops.
Oral Care (if applicable): If the mouth is affected, maintain good oral hygiene, using a soft toothbrush and avoiding acidic or spicy foods.
How long does an outbreak last?
An outbreak of erythema multiforme typically lasts between 2 to 4 weeks. In some cases, it may resolve more quickly, while in others, it may take longer. Recurrences are possible, particularly if triggered by recurrent HSV infections.
How is it diagnosed?
Clinical Examination: A doctor will examine the skin lesions and ask about the patient's medical history, including any recent infections, medications, or vaccinations.
Medical History: A thorough review of the patient's history, including previous HSV infections or medication use.
Skin Biopsy: In some cases, a skin biopsy may be performed to confirm the diagnosis and rule out other conditions. A small sample of skin is removed and examined under a microscope.
Blood Tests: Blood tests may be ordered to look for underlying infections, such as Mycoplasma pneumoniae or to rule out other conditions.
Timeline of Symptoms
Initial Phase (1-3 days): The first symptoms may be mild, such as a slight itching or burning sensation on the skin. Small, red spots may appear.
Development of Lesions (3-7 days): The characteristic target lesions begin to develop. They typically start as small, red macules (flat spots) that evolve into raised papules (bumps). The lesions gradually enlarge and develop the characteristic three-zone appearance.
Peak Phase (1-2 weeks): The rash reaches its peak, with the greatest number and size of lesions. Mucous membrane involvement (if present) may also be most severe during this phase.
Resolution Phase (2-4 weeks): The lesions gradually begin to fade and resolve. New lesions may continue to appear for a short time, but their number decreases. Any ulcers or blisters on the mucous membranes begin to heal.
Important Considerations
Severity: EM can range from mild to severe. EM minor usually involves only the skin, while EM major involves the skin and mucous membranes.
Stevens-Johnson Syndrome (SJS) / Toxic Epidermal Necrolysis (TEN): It is crucial to differentiate EM from SJS/TEN, which are more severe and life-threatening conditions that also cause skin rashes and mucous membrane involvement. SJS/TEN are usually triggered by medications and involve more extensive skin detachment than EM.
Recurrence: EM can recur, especially if triggered by recurrent HSV infections. Prophylactic antiviral medication may be considered for individuals with frequent recurrences.
Underlying Cause: Identifying and treating the underlying cause is essential for managing EM and preventing recurrences.
Medical Supervision: Individuals with EM should be monitored by a healthcare professional, especially if they have severe symptoms or mucous membrane involvement.