Contact Dermatitis: This is a common condition that can cause a rash and lymphadenopathy in the axillary region, often due to an allergic reaction to deodorants, antiperspirants, or other personal care products.

Eczema (Atopic Dermatitis): A chronic skin condition characterized by itchy, inflamed skin, which can lead to lymphadenopathy due to the body's immune response.
Folliculitis: An inflammation of the hair follicles, often caused by bacterial or fungal infections, which can cause a rash and lymphadenopathy in the axillary region.
Psoriasis: A chronic autoimmune condition that can cause skin lesions and lymphadenopathy, although it less commonly presents in the axillae.

Lymphoma: Although less common, lymphoma can present with lymphadenopathy and skin lesions, making it crucial not to miss this potentially life-threatening diagnosis.
Infectious Diseases (e.g., Tuberculosis, Cat-Scratch Disease): Certain infectious diseases can cause lymphadenopathy and skin rashes, and missing these diagnoses could lead to severe consequences.
Breast Cancer: In rare cases, breast cancer can metastasize to the axillary lymph nodes, causing lymphadenopathy, and may be associated with skin changes or rashes in the axillary region.

Sarcoidosis: A condition characterized by the growth of granulomas in various parts of the body, which can cause lymphadenopathy and skin lesions, including in the axillary region.
Hidradenitis Suppurativa: A chronic skin condition that can cause painful lesions and abscesses in the axillary region, potentially leading to lymphadenopathy.
Cutaneous T-Cell Lymphoma: A rare type of skin cancer that can cause skin lesions and lymphadenopathy, including in the axillary region.