Erythema Nodosum

What is erythema nodosum?

Erythema nodosum (EN) is an inflammatory skin condition that presents as tender, red, raised nodules, primarily on the shins. It represents a type of panniculitis, meaning inflammation of the subcutaneous fat. The exact cause of this condition can vary, but often it may be linked to another underlying health issue or remain unidentified.

What causes erythema nodosum?

Several factors and conditions can trigger erythema nodosum. In general your dermatologist will check bloodwork and do a thorough history and physical to assess for these.

• Infections: like streptococcal infections, tuberculosis, and some fungal infections

• Medications: such as oral contraceptives, certain antibiotics, and some anti-tuberculous drugs

• Autoimmune diseases: for instance, inflammatory bowel disease or Behçet's disease

• Pregnancy

• Internal Conditions: like sarcoidosis and some malignancies

• Unknown causes in many cases

What are the symptoms of erythema nodosum?

The primary symptom of erythema nodosum is the appearance of painful, red nodules on the shins. Other characteristics and symptoms include:

• Nodules' size: ranging from 1 to 5 cm

• Color change: nodules transition from red to purple and then brownish-yellow as they age

• Joint pain: often in the ankles, knees, and wrists

• Accompanying symptoms: such as fever, fatigue, and malaise

• Resolution: nodules usually resolve without scarring over 3-6 weeks

How do I treat erythema nodosum?

Treatment for erythema nodosum aims to relieve symptoms and address any underlying cause:

• NSAIDs: like ibuprofen for pain and inflammation

• Potassium iodide: for certain cases when other treatments don’t work

• Corticosteroids: used in severe instances or when related to specific conditions

• Addressing root cause: like treating an identified infection or discontinuing a triggering medication

• Rest and leg elevation: to alleviate discomfort and swelling

How do I prevent erythema nodosum?

Prevention methods for erythema nodosum involve:

• Medical check-ups: particularly if associated with ongoing conditions like inflammatory bowel disease

• Avoiding medications: that are known or suspected triggers

• Immediate treatment of infections: to prevent erythema nodosum in susceptible individuals