II. Epidemiology
- Incidence: 1-5 per 100,000
- Age: Peaks in 20-30 year range (up to age 50 years)
- Gender
- Adults: Women predominate by a factor of 6 fold
- Children: Boys and girls are equally affected
III. Pathophysiology
- Prototype of septal Panniculitis
- Erythema Nodosum is the most common cause of Paniculitis (subcutaneous fat inflammation)
- Cutaneous Type IV delayed Hypersensitivity response
IV. Causes
- Idiopathic or primary (up to 55% of cases)
- All other causes are considered secondary
- Infection
- Streptococcal Pharyngitis (up to 48% of EM cases, most common cause in children)
- Infectious Mononucleosis
- Mycoplasma
- Chlamydia
- Coccidioidomycosis
- Histoplasmosis
- Yersinia enterocolitis (in europe)
- MycobacteriaTuberculosis (see Granulomatous disease)
-
Granulomatous disease
- Tuberculosis
- Sarcoidosis (up to 25% of cases)
- Behcet Syndrome
- Inflammatory Bowel Disease
- Drug Reaction (up to 10% of cases)
- Miscellaneous
- Pregnancy
- Malignancy (e.g. Leukemia)
V. Symptoms
- Prodrome: Acute phase response (1-3 weeks before rash)
- Rash
- Painful "bumps" on legs
VI. Signs
- Characteristics
- Course
- Initially firm
- Later become fluctuant
- Involute over 2 week period
- May appear Bruised during healing
- Heal completely within 2 months
- No ulcerations, atrophy or scarring
- Distribution
- Lesions change color over time
- Evolve from red to purple to brown
- Typically fades without scarring in a few weeks (up to 6 weeks)
VII. Clinical variants
VIII. Labs
- Complete Blood Count (CBC) with Leukocytosis
- Sedimentation Rate (ESR) increased
- C-Reactive Protein increased
- Tuberculin Skin Test (PPD)
- Antistreptolysin-O titer and streptococcal throat swab
- Titer increase 30% at four weeks after onset suggests Streptococcus as cause
- Consider sending stool for Ova and Parasites
- Skin Biopsy (indicated in atypical cases)
- Inflammation confined to subcutaneous fat
- Acute lesions
- Septal widening
- Vessel wall inflammation
- NO Vasculitis
- Chronic lesions
- Giant cells
- Granulomas may be present
IX. Imaging
X. Differential Diagnosis
- Common
- Alpha-1 Antitrypsin Deficiency
- Lupus Panniculitis
- Lymphoma (cytophagic histiocytic Panniculitis)
- Less common
XI. Management
- NSAIDs
- Bed rest with leg elevation
- Support stockings
- Treat underlying cause
-
Potassium Iodide 300-900 mg/day for one month
- Risk of Hyperthyroidism
- Consider Systemic Corticosteroids
- Contraindicated in Bacterial Infection or cancer
- Prednisone 60 mg daily and taper
- Intralesional injections of Corticosteroids
XII. Course
- Most often resolves in 3-6 weeks
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Definition (MSH) | An erythematous eruption commonly associated with drug reactions or infection and characterized by inflammatory nodules that are usually tender, multiple, and bilateral. These nodules are located predominantly on the shins with less common occurrence on the thighs and forearms. They undergo characteristic color changes ending in temporary bruise-like areas. This condition usually subsides in 3-6 weeks without scarring or atrophy. |
Definition (CSP) | erythematous eruption commonly associated with drug reactions or infection and characterized by inflammatory nodules that are usually tender, multiple, and bilateral; these nodules are located predominantly on the shins with less common occurrence on the thighs and forearms; they undergo characteristic color changes ending in temporary bruise-like areas; this condition usually subsides in 3-6 weeks without scarring or atrophy. |
Concepts | Disease or Syndrome (T047) |
MSH | D004893 |
ICD9 | 695.2 |
ICD10 | L52 |
SnomedCT | 156363009, 200929004, 32861005 |
English | Erythema Nodosum, ERYTHEMA NODOSUM, erythema nodosum (diagnosis), erythema nodosum, Erythema Nodosum [Disease/Finding], nodosum erythema, Erythema;nodosum, Nodosum - erythema, Erythema nodosum, EN - Erythema nodosum, Erythema nodosum (disorder), erythema; nodosum, nodosum; erythema, Erythema nodosum, NOS |
French | ERYTHEME NOUEUX, Erythème noueux, Érythème noueux |
Portuguese | ERITEMA NODOSO, Eritema nodoso, Eritema Nodoso |
German | ERYTHEMA NODOSUM, Erythema nodosum |
Japanese | 結節性紅斑, ケッセツセイコウハン |
Swedish | Knölros |
Czech | erythema nodosum, Erythema nodosum |
Finnish | Kyhmyruusu |
Russian | ERITEMA UZLOVATAIA, ERITEMA NODOZNAIA, ЭРИТЕМА НОДОЗНАЯ, ЭРИТЕМА УЗЛОВАТАЯ |
Spanish | ERITEMA NODOSO, eritema nodoso, eritema nudoso (trastorno), eritema nudoso, Eritema nudoso, Eritema Nudoso |
Korean | 결절홍반 |
Croatian | ERITEM, NODOZNI |
Polish | Rumień guzowaty |
Hungarian | Erythema nodosum |
Norwegian | Knuterosen, Erythema nodosum |
Dutch | erytheem; nodosum, nodosum; erytheem, erythema nodosum, Erythema nodosum |
Italian | Eritema nodoso |