Erythema Nodosum

History Taking

Chief Complaint

• Tender, red, and warm lumps or nodules typically on the shins

History of Presenting Complaint

• Onset, duration, progression, and severity of skin changes

• Association with other symptoms like fever, weight loss, fatigue, joint pain, cough, diarrhea

• Variation in skin changes with movement, time of day, exposure to heat/cold, etc.

• Previous similar episodes

System Review

• Joint symptoms, such as pain or swelling (may indicate associated arthritis)

• Respiratory symptoms, such as cough, shortness of breath (suggestive of sarcoidosis, tuberculosis)

• Gastrointestinal symptoms, such as diarrhea, abdominal pain (suggestive of inflammatory bowel disease)

• Eye symptoms, such as redness, pain, or blurred vision (suggestive of uveitis)

Past Medical History

• Known diagnosis of any diseases associated with erythema nodosum such as:

  • Inflammatory bowel disease (Crohn's disease, ulcerative colitis)

  • Sarcoidosis

  • Tuberculosis

  • Streptococcal infection

  • Behçet's disease

• History of recurrent throat infections (streptococcal pharyngitis)

Drug History

• Recent start of any medications, such as oral contraceptives, antibiotics (e.g., amoxicillin, sulfonamides), anti-TNF alpha drugs

Family History

• History of any familial diseases associated with erythema nodosum such as inflammatory bowel disease, sarcoidosis

Personal History

• Any recent stressful events (stress can sometimes trigger erythema nodosum)

• Lifestyle habits like smoking (associated with increased risk of sarcoidosis, Behçet's disease)

Social History

• Occupational exposure to silica, beryllium (related to sarcoidosis)

• Contacts with TB patients

• Exposure to group A streptococcus (e.g., working with children)

Travel History

• Recent travel to areas endemic for tuberculosis or fungal diseases

Vaccine History

• Vaccination history for tuberculosis (BCG vaccine)

• Recent vaccination (some vaccines like hepatitis B vaccine can cause erythema nodosum)

OBG History

• Use of contraceptive pills (associated with erythema nodosum)

• Recent pregnancy (erythema nodosum can occur in pregnancy)

Physical Examination

General Examination

• Patient may appear unwell, feverish

• Painful, erythematous nodules, typically located on the anterior surface of the lower legs (shins)

• Signs of weight loss if associated with underlying systemic disease

Examination of the Hands and Arms

• Palpable purpura or other skin lesions in systemic vasculitis

• Joint tenderness or swelling suggestive of associated arthritis

Examination of the Face

• Eyes: Scleral injection, uveitis, or conjunctivitis that may be seen in conditions like sarcoidosis, Behçet's disease

• Mouth: Aphthous ulcers indicative of Behçet's disease

Neck Examination

• Lymphadenopathy could suggest an underlying systemic disease such as sarcoidosis or tuberculosis

Cardiac Examination

• Although uncommon, heart murmurs or other signs suggestive of endocarditis, especially if erythema nodosum is thought to be secondary to a streptococcal infection

Respiratory Examination

• Crackles, decreased breath sounds, or other abnormalities suggestive of pulmonary sarcoidosis or tuberculosis

Abdominal Examination

• Tenderness, guarding, or other signs suggestive of inflammatory bowel disease (Crohn's disease, ulcerative colitis)

• Hepatosplenomegaly in sarcoidosis or systemic infections like tuberculosis

Neurological Examination

• Not typically relevant in erythema nodosum, unless there's a suspicion of neurosarcoidosis based on the clinical scenario

Additional Examinations

• Joint examination: Swelling, redness, or limitation of movement indicative of associated arthritis

• Examination of other skin areas for lesions suggesting a systemic vasculitis or other dermatological conditions

Investigations

Laboratory Tests

• Full blood count: to assess for anemia, leukocytosis suggestive of infection or inflammation

• Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP): elevated in inflammatory conditions

• Liver function tests: abnormalities may be seen in sarcoidosis or hepatic involvement of other systemic diseases

• Kidney function tests: to assess for renal involvement in systemic disease

• Urinalysis: proteinuria or hematuria suggestive of renal involvement

• Throat swab for culture: if recent streptococcal infection is suspected

• Antistreptolysin O (ASO) titers: elevated in recent streptococcal infection

• Tuberculin skin test or interferon-gamma release assay (IGRA): if tuberculosis is suspected

• Autoantibodies (e.g., ANCA, ANA): if vasculitis or connective tissue disease is suspected

• Stool culture and examination: if inflammatory bowel disease is suspected

Imaging

• Chest X-ray: for signs of sarcoidosis (e.g., bilateral hilar lymphadenopathy), tuberculosis, or other thoracic diseases

• CT chest: if further details needed following abnormal chest X-ray

• Abdominal ultrasound or CT scan: for signs of inflammatory bowel disease, hepatic or splenic involvement

Invasive Tests

• Skin biopsy: for direct histological confirmation of erythema nodosum

• Bronchoscopy with biopsy or endobronchial ultrasound (EBUS): if sarcoidosis or pulmonary tuberculosis is suspected

• Colonoscopy with biopsy: if inflammatory bowel disease is suspected

Other Tests

• Tuberculin skin test or interferon-gamma release assay (IGRA): if tuberculosis is suspected

• Electrocardiogram (ECG): if cardiac sarcoidosis is suspected

• Ophthalmological examination: if ocular symptoms are present suggesting uveitis or other eye involvement

Management

General Management

• Education: Explanation about the benign and self-limiting nature of the condition in most cases

• Symptomatic relief: Rest, elevation of legs, application of cold packs

Medical Management

• Non-steroidal anti-inflammatory drugs (NSAIDs): Pain relief

• Potassium iodide: May be used in resistant cases

• Colchicine: Can be used if NSAIDs are contraindicated

• Corticosteroids: Used in severe cases or when associated with systemic diseases

• Disease-specific treatment: Management of underlying condition (e.g., antibiotics for infections, immunosuppressants for inflammatory bowel disease or sarcoidosis)

Surgical Management

• Not typically required for erythema nodosum itself

• May be necessary for managing some underlying conditions (e.g., resection in severe inflammatory bowel disease)

Other Management

• Regular follow-ups: To monitor response to treatment and progress of underlying diseases

• Referral to specialists: Depending on the underlying cause (e.g., Rheumatologist, Gastroenterologist, Respiratory Specialist)

• Physiotherapy: If joint involvement is causing significant mobility issues

Causes of Erythema Nodosum

• Infections

  • Bacteria: Streptococci, mycobacteria, Brucella, Mycoplasma

  • Viruses: Hepatitis B, infectious mononucleosis

  • Fungi

• Drugs

  • Sulphonamides

  • Sulphonylureas

  • Oral contraceptives

• Systemic disease

  • Inflammatory bowel disease

  • Malignancy

  • Sarcodosis

• Other: Pregnancy