Erythema Nodosum: Symptoms, Causes, Diagnosis and Treatment

Written by Medicover Team and Medically Reviewed by Dr Koppisetti Satya Naga Ravi Teja , Dermatologists

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1. Causes 2. Find a Doctor 3. Diagnosis 4. Treatment 5. FAQs

Erythema nodosum is an inflammatory condition that causes painful, red, tender lumps beneath the skin, most commonly on the front of the lower legs. It is often triggered by infections, medications, autoimmune diseases, pregnancy, or other underlying health conditions. Although the condition is usually self-limiting, identifying and treating the underlying cause is essential. Early diagnosis and appropriate treatment can help relieve pain, reduce inflammation, and support a faster recovery while preventing complications.

What are the Symptoms of Erythema Nodosum?

The hallmark of erythema nodosum is the presence of tender, erythematous nodules, typically on the lower extremities. These nodules can evolve over days, initially appearing bright red and later becoming bluish or brownish as they resolve. Additional symptoms may include:

Fever: Often low-grade
Fatigue
Joint pain: Particularly in the ankles, knees, and wrists
Swelling: Around the affected nodules

What are the Causes of Erythema Nodosum?

Erythema nodosum is often a hypersensitivity reaction to various stimuli. Understanding these triggers is crucial for effective management.

Infections

Various infections can precipitate erythema nodosum, including:

Streptococcal Infections: Particularly in children, streptococcal pharyngitis is a common trigger.
Tuberculosis: A historical cause of EN, although less common in developed countries due to effective TB control measures.
Fungal Infections: Conditions such as coccidioidomycosis, histoplasmosis, and blastomycosis can also lead to EN.
Viral Infections: Including HIV, hepatitis B, and Epstein-Barr virus.

Medications

Certain medications are known to induce erythema nodosum. These include:

Sulfonamides
Oral contraceptives
Penicillins
Nonsteroidal anti-inflammatory drugs (NSAIDs)

Systemic Diseases

Erythema nodosum can be associated with various systemic conditions:

Inflammatory Bowel Disease (IBD): Both Crohn's disease and ulcerative colitis have been linked to EN.
Sarcoidosis: EN is a common dermatologic manifestation of sarcoidosis.
Rheumatologic Conditions: Such as systemic lupus erythematosus and Behcet's disease.

Pregnancy

Erythema nodosum can also occur during pregnancy, likely due to hormonal changes and immune modulation. While generally benign, it requires careful management to ensure maternal and fetal health.

When to See a Doctor for Erythema Nodosum?

If you develop painful red nodules on your legs, especially with fever, joint pain, or persistent swelling, consult a dermatologist, rheumatologist, or general physician. Early evaluation helps identify the underlying cause and prevents complications associated with infections or inflammatory diseases.

You should see a doctor if you have:

Painful, tender nodules that do not improve.
Persistent fever or swollen joints.
Recurring episodes of erythema nodosum.

Get medical help immediately if:

Difficulty breathing or persistent chest pain.
Rapidly worsening swelling or severe leg pain.
High fever with signs of a serious infection.

These could be signs of a serious complication like Erythema Nodosum, which needs urgent care.

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How Is Erythema Nodosum Diagnosed?

Diagnosing erythema nodosum involves a combination of clinical evaluation and diagnostic tests.

Clinical Examination

A thorough history and physical examination are essential. Physicians should inquire about recent infections, medication use, and systemic symptoms. The characteristic appearance and distribution of the nodules often provide key diagnostic clues.

Laboratory Tests

Complete Blood Count (CBC): To check for signs of infection or inflammation.
Erythrocyte Sedimentation Rate (ESR) and C-reactive Protein (CRP): These inflammatory markers are typically elevated in EN.
Throat Culture: To identify streptococcal infections.
Tuberculin Skin Test: To rule out tuberculosis.
Chest X-ray: Particularly in cases suspected to be associated with sarcoidosis or tuberculosis.

Biopsy

In uncertain cases, a skin biopsy may be performed. Histopathologic examination typically reveals septal panniculitis without vasculitis, confirming the diagnosis.

What are the Treatment of Erythema Nodosum?

Managing erythema nodosum involves addressing the underlying cause, alleviating symptoms, and promoting the resolution of nodules.

Addressing Underlying Causes

Infections: Appropriate antibiotics or antifungal treatments should be administered.
Medication-induced EN: Discontinuation of the offending drug is imperative.
Systemic Diseases: Management of the primary condition (e.g., immunosuppressive therapy for sarcoidosis or IBD).

Symptomatic Treatment

Nonsteroidal anti-inflammatory drugs (NSAIDs), Such as ibuprofen or naproxen, reduce pain and inflammation.
Potassium Iodide: Though not commonly used, it can be effective in some cases.
Corticosteroids: Systemic corticosteroids may be considered for severe or refractory cases, although their use should be cautious due to potential side effects.