Method
Upon presentation of the patients with tender, erythematous nodules on the lower extremities, a comprehensive differential diagnosis was considered. The differential diagnosis for EN includes infectious causes (e.g., streptococcal infections, tuberculosis, Yersinia, Mycoplasma, Chlamydia, Histoplasma, Coccidioides, and HIV), inflammatory conditions (e.g., sarcoidosis, inflammatory bowel disease, and Behçet’s disease), malignancies (e.g., lymphoma, leukemia, and solid tumors), medications (e.g., oral contraceptives, sulfonamides, and certain antibiotics), and other causes (e.g., pregnancy, Sweet’s syndrome, and idiopathic EN).
A thorough clinical evaluation and targeted laboratory investigations were conducted to establish the diagnosis and identify the underlying cause of EN in this familial cluster. Physical examination included a detailed assessment of the skin lesions, their distribution, size, color, and tenderness, as well as a comprehensive systemic examination to detect any associated signs or symptoms. Laboratory tests included a complete blood count to evaluate for leukocytosis, ASO titers to detect recent streptococcal infection, ESR and CRP levels to assess underlying inflammation, and renal and hepatic function tests to rule out systemic involvement. Imaging studies, such as chest radiographs, were performed to screen for pulmonary involvement or associated conditions, and PCR tests for COVID-19 were conducted to exclude this as a potential cause. Although not performed in this case, a deep incisional or excisional biopsy of the nodules may be considered to confirm the diagnosis of EN and exclude other nodular lesions.
The management of EN in this familial cluster focused on providing supportive care to alleviate symptoms, as the patients were referred to the doctor after the optimal window for initiating antibiotic therapy had passed. Due to the late presentation, the golden time for antibiotic initiation had ended, precluding the use of antibiotics to treat the underlying streptococcal infection. Supportive measures included rest, leg elevation to reduce swelling and discomfort, nonsteroidal anti-inflammatory drugs (NSAIDs) to manage pain and inflammation, and cool compresses applied to the affected areas to provide symptomatic relief. Close follow-up was ensured to assess the response to these supportive measures, monitor for potential complications, and evaluate for any underlying systemic diseases, particularly in the setting of familial EN. Although antibiotics are typically the mainstay of treatment for EN secondary to streptococcal infection, the delayed presentation in this case necessitated a focus on symptom management and supportive care.