What are these tender nodules?
Erythema Nodosum is a skin disease that causes tender nodules, usually on the lower legs. Erythema nodosum is more common in women between the ages of 20 and 30, but can occur in anyone.

What caused it?
There are many causes of erythema nodosum. These include birth control pills, medications, bacterial infections, fungal infections, viral infections, and tuberculosis. If the doctor suspects erythema nodosum, the first step is to have a lesion biopsied. A skin biopsy is the only way to prove the diagnosis. If the biopsy proves that you have erythema nodosum, the doctor will then try to determine the cause of your condition. This may involve lab work and skin tests. Erythema nodosum is not dangerous or contagious. The disease usually goes away by itself after the underlying cause is found.

How do I treat it?
An aspirin-like drug called Indocin, Vioxx, or Embrel often improves the condition. Gentle heat, provided by a warm, soapy wash cloth held over the area for 30 minutes, three to four times a day, often speeds up the healing process.