Erythema nodosum is a skin infection in the fatty layer of skin (panniculitis). It is common in young people from ages 12-20. It can be idiopathic, meaning there is no direct cause, be genetic/familial, or result from an infection such as a streptococcal infection.
One of the first signs of erythema nodosum is having flu-like symptoms or feeling weak and tired in general. The skin becomes inflamed and red (erythema), with bumps or nodules. These bumps are tender, sore, and sometimes hard to the touch when there are a few next to each other. These bumps vary in size, ranging from the size of a dime to the size of a quarter. Normally, there are multiple bumps on both sides of the body. The bumps are primarily on the shins and sometimes on the thighs and forearms. While they start as being red or purplish, the color changes as the illness progresses. They may become purple, brown, yellow, or green in color and ultimately become bruise-like at the end stages.
Other symptoms of erythema nodosum that sometimes occur are joint pain, fever, and fatigue. Sometimes Crohn’s disease and irritable bowel syndrome (IBS) are present at the same time in the individual. Erythema nodosum will typically go away in 3-6 weeks on its own and without treatment. It does not cause scarring or atrophy. If you or a family member has been diagnosed with erythema nodosum, talk with your doctor about the most current treatment options.
Description Last Updated: Feb 12, 2018