Erythema nodosum in Adult
Associated bacterial, viral, fungal, and protozoal infections are numerous and include Streptococcus, Shigella, Yersinia, Histoplasma, Coccidioides, HIV, Giardia, and COVID-19. Tuberculosis (TB) remains an important cause in areas of endemic disease. Less commonly, Campylobacter, Salmonella, cat-scratch disease, Chlamydia, syphilis, pertussis, leprosy, hepatitis B, blastomycosis, and sporotrichosis may be precipitants. Inflammatory associations include sarcoidosis, inflammatory bowel disease, Sjögren syndrome, reactive arthritis, and Behçet disease. In Crohn disease, EN may occur even if the Crohn disease is well controlled. Malignancy, such as lymphoma or leukemia, is a rare cause of EN.
The eruption typically persists for 3-6 weeks and spontaneously regresses without scarring or atrophy. Recurrences are sometimes seen, especially with reoccurrence of the precipitating factor(s).
Arthralgias, often in the ankles and knees, are reported by a majority of patients, regardless of the etiology of EN.
No specific genetic predilection exists except for in relation to the underlying diseases (eg, sarcoidosis is more common in Black individuals). EN can occur at any age, but most cases occur between the ages of 20 and 45, particularly in women. Sex incidence before puberty is about equal.
Löfgren syndrome is a benign variant of sarcoidosis with EN and bilateral enlargement of the hilar lymph nodes. It occurs more commonly in females, especially during pregnancy.
Subacute nodular migratory panniculitis is a variant of EN. It is often unilateral, more focal, and painless. Gradual expansion is characteristic.
L52 – Erythema nodosum
32861005 – Erythema nodosum
Differential Diagnosis & Pitfalls
- Nodular vasculitis / erythema induratum is typically on the posterior calves.
- Primary infectious panniculitis (see panniculitis) occurs through septic seeding or direct inoculation of a variety of infectious organisms. Tissue culture and polymerase chain reaction (PCR) aids in diagnosis.
- Pancreatic panniculitis favors the lower legs but is often ulcerated.
- Lupus panniculitis favors the face and upper trunk. Most cases are not associated with systemic lupus erythematosus.
- Panniculitis of dermatomyositis (abdomen, thighs, arms) may be the first manifestation of dermatomyositis.
- Granulomatous panniculitis is a manifestation of subcutaneous granuloma annulare or sarcoidosis.
- Cold panniculitis typically presents on the cheeks in children. In adults, it may occur on any body site exposed to cold temperatures. Lateral thigh involvement of horseback riders has been described.
- Injections, including iatrogenic and factitial.
- Alpha-1 antitrypsin deficiency panniculitis is extremely rare in children but has been reported as an initial manifestation of the disease. Lesions frequently ulcerate.
- Subcutaneous T-cell lymphoma
Drug Reaction Data