Erythema nodosum: why diagnosing the underlying disease is important

Erythema nodosum, which is an inflammatory lesion of the skin and subcutaneous vessels, is common in clinical practice and may resolve without drug therapy. However, it usually signals a serious internal disease. Therefore, with erythema nodosum, the doctor should conduct a thorough interview and a comprehensive examination of the patient in order to effectively eliminate the underlying disease and reduce the severity of the local inflammatory process.

What is erythema nodosum

Erythema nodosum – is an acquired acute or subacute/chronic disease characterized by the presence of deep erythematous tender nodules typically located on the extensor surfaces of the lower extremities.

Erythema nodosum (ES) is an idiopathic disease. This reaction is believed to be mediated by immune mechanisms and develops in response to various antigenic stimuli: viral, bacterial, deep fungal infections, lymphomas, inflammatory bowel disease, and drugs (especially oral contraceptives).

Erythema nodosum is a septal granulomatous panniculitis. The acute form manifests itself in the form of red, painful nodes on the anterior surface of the lower leg, which are resolved within a few weeks. It may be accompanied by fever and joint pain. Angina, diarrhea, recurrent abdominal pain, hepatitis or a history of tuberculosis may indicate the cause of the disease.

In the chronic form, subcutaneous non-tender nodules coalesce into plaques with central resolution and persist for several months.

Possible causes of erythema nodosum

One of the main causes of acute EU is b–hemolytic streptococcus group A, especially among children. UE usually develops 2-3 weeks after acute tonsillitis. A frequent cause of UE is the use of drugs, mainly antibiotics, sulfonamides and oral contraceptives, which are used especially often. EU usually develops after 10-14 days from the start of the drug. Given the possibility of drug-induced ES, special attention should be paid to this when collecting patient history.

Along with pyoderma gangrenosum, EU is the most common skin lesion in inflammatory bowel diseases (ulcerative colitis and Crohn's disease). Often, the development of UE correlates with an exacerbation of the underlying disease. In the presence of arthritis, EU with these diseases occurs 4 times more often than without it.

It is usually not difficult to determine the cause of ES. A thorough study of the anamnesis and a careful examination of the patient, the results of laboratory and instrumental studies in most cases help to make the correct diagnosis.

Erythema nodosum: general therapeutic recommendations

Treatment of erythema nodosum should be aimed at eradicating the underlying disease. Of great importance is bed rest, tk. at such patients the orthostatism is usually sharply expressed. To reduce inflammation and pain, non-steroidal anti-inflammatory drugs (diclofenac 100-150 mg/day, indomethacin 100-150 mg/day, naproxen 500 mg/day, ibuprofen 1200 mg/day), vascular drugs (pentoxifylline) are used.

In chronic EU, to intensify the anti-inflammatory and absorbable effect, it is recommended to use potassium iodide (3% solution, 1 tablespoon 2–3 times a day, mixed with milk or fruit juice). The effect of potassium iodide in UE is associated with its ability to stimulate the release of heparin by mast cells. Iodine preparations are contraindicated in pregnant women (contribute to the development of goiter in the fetus) and should be administered with caution to patients with thyroid pathology, because. Cases of severe hypothyroidism induced by potassium iodide have been described.

For local treatment, anti-inflammatory, resolving infiltrate and restoring microcirculation agents are used. Compresses are prescribed with 5% dibunol liniment, 5-10% ichthyol solution. Applications with a 33% solution of dimexide are an effective and safe method of local therapy for UE, easily performed on an outpatient basis.

For local treatment of EU, physiotherapeutic procedures are also recommended: phonophoresis with 5% dibunol liniment, ozocerite applications, phonophoresis with lidase, heparin, hydrocortisone, inductothermy, ultrasound therapy, magnetotherapy, UHF therapy and exposure to laser beams directly on lesions.

In case of high inflammatory activity or insufficient effectiveness of the above treatment, the appointment of prednisolone per os 30-40 mg per day for 8-10 days is indicated, followed by a gradual slow decrease in the dose until complete withdrawal.

In chronic UE, it is advisable to prescribe Plaquenil at a dose of 0.4 g/day. within 2–3 months.

Thus, erythema nodosum requires careful questioning and a comprehensive examination of the patient. Treatment of EU is aimed at eliminating the underlying disease and reducing the duration and severity of the local inflammatory process. Despite the possibility of recurrence, the course of ES is usually favorable.