Erythema nodosum is an acute inflammatory nodular skin disease caused by various factors, characterized by non-specific inflammation of the subcutaneous tissue, commonly occurring on the extensor surfaces of the lower legs. Clinically, it presents as scattered bright red round or oval nodules, which may be painful or tender to touch, and heals without scarring. This condition is more common in young women and tends to occur in spring and autumn. In China, subcutaneous nodules are a frequent cause of the disease, but it can also be triggered by infections such as hemolytic streptococcus, viruses, fungal infections, or certain medications. Therefore, identifying the underlying cause is crucial for effective treatment.

bubble_chart Clinical Manifestations

1. lack of strength, fever, joint and muscle pain;
2. The typical rash consists of scattered, varying-sized bright red round or oval nodules, slightly raised above the skin surface, smooth in texture, moderately firm, with spontaneous pain and tenderness;
3. It often occurs symmetrically on the extensor sides of the lower legs and may sometimes merge to form large masses;
4. The affected area shows edema but does not ulcerate.

bubble_chart Diagnosis

1. History of upper respiratory tract infection or subcutaneous nodules;
2. Symptoms before onset include fever, fatigue, joint and muscle pain, and even high fever;
3. Bright red, round or oval nodules with a smooth surface, accompanied by spontaneous pain and tenderness;
4. Histopathology reveals septal panniculitis;
5. Increased erythrocyte sedimentation rate and elevated anti-streptolysin O (ASO) levels;
6. Positive subcutaneous nodule bacillus test.

bubble_chart Treatment Measures

1. Identify and eliminate the disease cause, avoid various inducing factors;
2. Non-specific anti-allergic treatment;
3. Corticosteroid therapy;
4. Symptomatic supportive treatment.

1. For mild cases, mainly use oral vitamin C, vitamin E, and non-steroidal anti-inflammatory drugs;
2. For ordinary cases, oral or intramuscular administration of vitamin C, E, and non-steroidal anti-inflammatory drugs or small doses of corticosteroids are more effective;
3. For severe cases, moderate to high doses of corticosteroids or aminophenol and colchicine are used for treatment.

bubble_chart Cure Criteria

1. Cure: The rash completely disappears;
2. Improvement: Most of the rash subsides;
3. No cure: The rash does not subside or new rashes still appear.