Axillary Lymphadenitis

Axillary lymphadenitis is inflammation of the axillary lymph nodes draining the arm, hand, breast and chest wall. Causes include bacterial infection of the hand or arm (Staphylococcus, Streptococcus), cat scratch disease, tuberculosis, brucellosis, BCG vaccine adenitis in infants, breast infection or cancer, lymphoma, and vaccine or injection reactions.

• BCG adenitis occurs in about 1 percent of vaccinated infants (usually left axilla), more often with a high dose or incorrect depth.

Tender swelling in the axilla, with fever or erythema when infected; chronic nodes may be painless.

• BCG adenitis: ipsilateral node 2 to 6 months after vaccination, non suppurative (self-limited) or suppurative with sinus.
• Differential diagnosis: hidradenitis suppurativa, sebaceous cyst, lipoma, breast carcinoma, lymphoma, leukaemia, silicone implant reaction, deodorant folliculitis, accessory breast tissue, tuberculosis, cat scratch disease, filarial, metastatic melanoma.
• Complications: abscess, sinus, arm lymphoedema, cellulitis, scarring, disseminated BCG disease in immunodeficiency.

Clinical, with examination of the arm, hand, breast and other nodes.

• Ultrasound; fine needle aspiration for culture, Xpert MTB/RIF and cytology; full blood count, CRP.
• HIV test (including maternal HIV and infant status in BCG adenitis); Bartonella and Brucella serology; breast imaging in adults; excision biopsy if non diagnostic.
• Immunodeficiency work up for disseminated BCG disease.

Treat the source, drain pus and exclude malignancy.

• Supportive: warm compress, arm rest, analgesia (paracetamol 1 g, 15 mg/kg), hygiene, treat hand and arm lesions.
• Pharmacological: pyogenic axillary lymphadenitis: flucloxacillin 500 mg to 1 g four times daily for 7 to 10 days (children 12.5 to 25 mg/kg four times daily), clindamycin 300 to 450 mg three times daily if allergic. Cat scratch disease: azithromycin 500 mg then 250 mg daily for 4 days. Brucellosis: doxycycline 100 mg twice daily with rifampicin 600 to 900 mg daily for 6 weeks. Tuberculosis: isoniazid, rifampicin, pyrazinamide and ethambutol for 2 months then isoniazid and rifampicin for 4 months. Non suppurative BCG adenitis: observation, no drug therapy; suppurative BCG adenitis: needle aspiration, and in immunodeficiency or disseminated BCG, isoniazid 10 mg/kg with rifampicin 15 mg/kg and ethambutol 20 mg/kg daily for 6 months under specialist care (pyrazinamide excluded as BCG is intrinsically resistant).
• Procedures: needle aspiration of suppurative nodes (repeated); incision and drainage if large abscess; excision of persistent node.
• Special groups: pregnancy and lactation, flucloxacillin or cefalexin; infants, observation for BCG adenitis and HIV test; HIV, suspect disseminated BCG or tuberculosis; breast cancer survivors, protect the arm.
• Red flags: hard fixed nodes, associated breast mass, lymphoedema, weight loss, night sweats, fever with sepsis, multiple node groups.
• Follow-up: review at 2 weeks; ultrasound or biopsy if persistent beyond 4 to 6 weeks; BCG adenitis monthly for 6 months.