Symptoms:

The characteristic tender, red nodules of erythema nodosum usually appear on the shins:

• One or more nodules
• Painful, reddened
• Located on the anterior surface of the lower leg
• Occasionally located on the arms or trunk
• May feel warm to touch
• Not ulcerated

Accompanying symptoms include the following:

• Fever
• General ill feeling (malaise)
• Joint aches
• Skin redness, inflammation, or irritation
• Swelling of the leg or other affected area

Signs and tests:

The diagnosis is primarily based on the appearance of the skin nodules. Biopsy of a nodule may show characteristic changes (septal panniculitis).