This disease is an allergic inflammatory skin condition primarily affecting the small blood vessels in the superficial dermis, caused by various factors. It commonly occurs in the limbs, particularly around the calves and ankles. Clinical manifestations include papular purpura, wheals, small chickenpox-like lesions, multiform erythema, and small nodules, with erythema and nodules being the most frequent. The course of the disease is chronic and can persist for several years. It often affects young adults, with potential triggers including bacterial or viral infections and certain medications. Given the diverse manifestations and prolonged course of the disease, early and accurate diagnosis can help shorten the duration, alleviate discomfort, and improve treatment outcomes.

bubble_chart Diagnosis

Clinical manifestations 1. Initial stage [first stage]: Skin lesions present as red maculopapules and purpura the size of foxtail millet grains; 2. Chickenpox-like lesions, blood blisters, and nodules the size of soybeans appear on the erythematous base; 3. Shallow ulcers may form after chickenpox lesions rupture or nodules necrose; 4. Chronic sexually transmitted disease cases often exhibit multiple coexisting lesions. 5. The rash is symmetrically distributed on both lower limbs and buttocks.

Diagnostic basis 1. Chronic course with recurrent episodes, predominantly distributed on both lower limbs; 2. Polymorphic lesions including erythema, papules, purpura, small chickenpox-like lesions, nodules, wheals, and ulcers; 3. Increased white blood cell count and elevated erythrocyte sedimentation rate; 4. Elevated anti-"O" titer; 5. Histopathology shows nonspecific panniculitis in the upper subcutaneous tissue and dermal inflammatory reactions;

Principles of Treatment 1. Identify and remove the disease cause, avoiding various inducing factors; 2. Non-specific anti-allergy treatment; 3. Reduce capillary permeability and fragility; 4. Corticosteroid hormone therapy; 5. Symptomatic supportive treatment.

Principles of Medication 1. For early mild cases, focus on oral antihistamines, vitamin C, and E; 2. For intermediate-stage [second-stage] ordinary cases, oral or intramuscular antihistamines, vitamin C, E, and intravenous calcium gluconate or low-dose corticosteroids are more effective; 3. For severe cases, prioritize intravenous medium to high-dose corticosteroids, while paying attention to supportive symptomatic treatment; 4. For cases with poor response to hormone therapy, consider trying treatments such as dapsone or colchicine.

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.