Erythema nodosum
Evidence: Unconfirmed
Names
Idiopathic erythema nodosum
Erythema nodosum of unknown etiology
EN
Description
Erythema nodosum is a condition that causes the fat layer just beneath the skin to become inflamed, forming swollen bumps 1 to 5 cm across. These bumps most frequently occur on the shins, and sometimes the thighs and forearms as well. The degree of inflammation may vary by day over a period of 3 to 6 weeks, after which time the bumps finally fade. The affected area may appear bruised for a period of up to a few months afterward, but most patients experience a full recovery with no scars. The cause is uncertain but is correlated with an over-reactive immune response following infection, medication, pregnancy, inflammatory conditions, vaccines, and autoimmune or other medical conditions. Treatments are available to relieve discomfort.
Patient Groups
Facebook Group: Erythema Nodosum: Support Group
Facebook Group: For People who have Erythema Nodosum
Bloggers
None found.
Prevalence
US Cases: 3,200 - 16000 [Requena 2001]. 1-5 per 100,000 persons
For adults, EN is more common among women, with a male-to-female ratio of 1:6.
Typical Age of onset
Typically 18-34 years of age, but may occur at any age.
[Leung 2018]
Symptoms
EN has three consistent phases, before, initial breakout and after breakout.
Before breakout:
Fever
Joint pain
Abdominal pain
Flu-like symptoms
Initial breakout:
Fever
Increased joint pain
Painful, symmetrical lumps 3-6 cm in diameter on the legs and knees, and sometimes thighs and forearms
Increased pain when standing
Swollen ankles
Enlarged lymph nodes
After breakout:
Lumps continue to grow for about 10 days
Lumps turn blue and yellow
Lumps disappear after 3-6 weeks
