Differential Diagnosis for Swelling in the Right Axillary Region
Single Most Likely Diagnosis
- Lymphadenitis or Lymphadenopathy: This is often due to infection or inflammation of the lymph nodes in the axillary region, which can be caused by bacterial, viral, or fungal infections. The proximity of the axilla to the breast and the presence of apocrine glands make it a common site for infections and subsequent lymph node enlargement.
Other Likely Diagnoses
- Breast Cancer with Axillary Lymph Node Involvement: Swelling in the axillary region can be a sign of breast cancer that has spread to the lymph nodes. This is particularly concerning in women, especially those with a history of breast cancer or strong family histories.
- Cat Scratch Disease: Caused by Bartonella henselae, this condition often results from a cat scratch or bite, leading to lymphadenopathy, commonly in the axillary region if the scratch or bite occurred on the arm.
- Axillary Abscess or Furuncle: An abscess or boil in the axillary region can cause significant swelling and pain. These are usually caused by Staphylococcus aureus and can be related to shaving, sweating, or poor hygiene.
- Lipoma or Other Benign Tumors: Benign growths like lipomas can occur in the axillary region, causing swelling. These are usually painless and may grow over time.
Do Not Miss Diagnoses
- Lymphoma: Both Hodgkin's and non-Hodgkin's lymphoma can present with lymphadenopathy in the axillary region. Although less common, missing a diagnosis of lymphoma can have severe consequences.
- Metastatic Cancer: Cancers from other parts of the body can metastasize to the axillary lymph nodes, causing swelling. This would be particularly concerning in patients with a known history of cancer.
- Tuberculosis or Atypical Mycobacterial Infection: Although less common in some regions, tuberculosis (TB) and atypical mycobacterial infections can cause lymphadenitis that may present with axillary swelling.
Rare Diagnoses
- Kikuchi-Fujimoto Disease: A rare, self-limiting condition that causes lymphadenitis, often in the cervical region but can also affect axillary nodes.
- Kimura Disease: A chronic inflammatory disorder that can cause lymphadenopathy and swelling, typically in the head and neck region but can occasionally involve the axilla.
- Castleman Disease: A rare disorder that involves an overgrowth of cells in the lymphatic system, which can cause lymphadenopathy, including in the axillary region.
- Sarcoidosis: Although more commonly affecting the lungs and lymph nodes in the chest, sarcoidosis can rarely cause lymphadenopathy in the axillary region.