Erythema nodosum is a skin condition characterized by tender, red bumps that typically appear symmetrically on the shins.
Understanding Erythema Nodosum
Erythema nodosum isn't a disease itself, but rather a reaction pattern in the skin that signals an underlying issue. These bumps, or nodules, are usually warm and painful to the touch. While the shins are the most common location, they can sometimes appear on other areas like the thighs, arms, or torso.
Symptoms of Erythema Nodosum
Besides the characteristic red and tender nodules, individuals with erythema nodosum may experience:
- Fever
- Fatigue
- Joint pain, especially in the ankles
- General feeling of being unwell (malaise)
Causes of Erythema Nodosum
In up to 55% of cases, the exact cause of erythema nodosum remains unidentified (idiopathic). However, several factors are known to trigger this condition:
- Infections: Bacterial (e.g., streptococcal infections, tuberculosis), fungal, or viral infections.
- Medications: Certain drugs, such as sulfonamides, penicillin, and oral contraceptives.
- Underlying Diseases: Conditions like inflammatory bowel disease (Crohn's disease, ulcerative colitis), sarcoidosis, and Behçet's disease.
- Pregnancy: Hormonal changes during pregnancy can sometimes trigger erythema nodosum.
Diagnosis and Treatment
Diagnosis usually involves a physical examination and a review of the patient's medical history. A skin biopsy may be performed to confirm the diagnosis and rule out other conditions. Further tests may be needed to identify the underlying cause.
Treatment focuses on addressing the underlying cause, if identified. Symptomatic relief may include:
- Rest and elevation of the affected limbs.
- Over-the-counter pain relievers such as ibuprofen or naproxen.
- Corticosteroid creams or injections to reduce inflammation.
- Potassium iodide (prescribed by a doctor) can sometimes be effective.
Prognosis
Erythema nodosum is usually a self-limiting condition, meaning it resolves on its own within a few weeks to months. The nodules may change color from red to bruised-looking as they heal. Recurring episodes are possible, especially if the underlying cause is not adequately addressed.
