Understanding Armpit Lumps: Causes, Symptoms & When to See a Doctor

A palpable axillary lump merits clinical evaluation. Common causes:

• Reactive Lymphadenopathy: Infection (local skin, upper respiratory, cat-scratch, mono), vaccination, autoimmune.
• Hidradenitis Suppurativa: Chronic follicular occlusion → painful nodules/abscesses/sinus tracts in axilla/groin.
• Lipoma: Soft, mobile, non-tender fatty tumor.
• Sebaceous Cyst: Firm, central punctum; may become infected.
• Fibrocystic Change Extension: Breast tissue extends into axilla (Tail of Spence); cyclic tenderness.
• Malignancy: Breast cancer metastasis, lymphoma, leukemia, soft tissue sarcoma (rare).

Evaluation

1. History: Duration, change, pain, systemic symptoms, breast changes.
2. Exam: Breast, axillae, supraclavicular, general lymphatics.
3. Imaging: Ultrasound (first-line), mammogram (women >30), MRI if needed.
4. Biopsy: Core needle or excisional if suspicious.

Do not self-diagnose; most are benign, but timely assessment rules out serious pathology.