What is the treatment for an infected lymph node in the axilla?

Treatment of Infected Axillary Lymph Node

Prompt initiation of antibiotic treatment targeting streptococcal organisms is the primary treatment for an infected axillary lymph node, particularly in patients with a history of axillary lymph node dissection or breast cancer treatment. 1

Immediate Management

Antibiotic Therapy

• Start empiric antistreptococcal antibiotics immediately without waiting for culture results, as bacterial cultures are rarely positive and should not delay treatment 2
• Antistreptococcal coverage is essential because streptococcal organisms are the most common causative pathogens in post-axillary dissection cellulitis 2
• Treatment is universally successful when appropriate antibiotics are initiated promptly 2

Clinical Assessment

• Evaluate for signs of cellulitis including erythema, warmth, tenderness, and swelling of the affected arm or axilla 3, 2
• Assess for underlying lymphedema, which significantly increases infection risk and may require concurrent management 2
• Determine if the patient has a history of axillary surgery, radiation therapy, or breast cancer treatment, as these create long-term risk for recurrent infections 1, 3, 2

Diagnostic Considerations

When to Pursue Tissue Diagnosis

• If the lymph node appears suspicious on ultrasound (abnormal cortical thickness, round shape, abnormal vascularity), perform ultrasound-guided fine needle aspiration or core biopsy to exclude malignancy 4
• Consider alternative diagnoses such as toxoplasmosis, which can mimic malignant lymphadenopathy 5
• Blood and tissue cultures have limited utility in typical post-surgical cellulitis but may be considered in atypical presentations 2

Special Populations at Risk

Post-Axillary Dissection Patients

• Women who have undergone axillary lymph node dissection face lifelong risk of cellulitis due to localized immune impairment 2
• The combination of axillary clearance and radiation therapy increases lymphedema risk to 40%, further elevating infection susceptibility 1
• Infection rates are notably higher in patients who received radiation therapy to the breast or chest wall after axillary dissection 3

Preventive Counseling

• Educate patients to seek immediate medical attention for any signs of arm or axillary infection 1
• Advise prompt treatment of any wounds on the ipsilateral arm 1
• Patient and physician awareness is the most effective tool to prevent secondary exacerbation of lymphedema 2

Common Pitfalls to Avoid

• Do not delay antibiotics while awaiting culture results, as cultures are rarely diagnostic and treatment delay worsens outcomes 2
• Do not assume all axillary lymphadenopathy is infectious—maintain suspicion for malignancy, particularly if imaging shows suspicious features 4, 5
• Recognize that radiation therapy significantly increases the frequency of inflammation and infection beyond what is commonly appreciated 3
• Address underlying lymphedema management, as appropriate lymphedema treatment likely reduces infection risk 2

Long-term Considerations

• Patients remain at risk for recurrent episodes of cellulitis throughout their lifetime after axillary dissection 2
• Mild symptoms including numbness (35%), pain (30%), and arm swelling (15%) are common 2-5 years post-dissection and may predispose to infection 3
• Episodes of infection or inflammation occur in approximately 8% of patients at some point after breast cancer diagnosis 3