A young woman presents with significant weight loss and dark purple lesions. What condition should you suspect?

The presentation of significant weight loss combined with dark purple lesions is highly indicative of HIV infection. This is particularly relevant because individuals with HIV can develop Kaposi's sarcoma, a type of cancer characterized by the appearance of dark purple or brown lesions on the skin or other tissues. These lesions occur due to the proliferation of blood vessels and are often associated with the immunocompromised state that HIV causes.

HIV infection leads to a significant decline in immune function, making individuals more susceptible to opportunistic infections and certain cancers. The weight loss observed, often referred to as "wasting syndrome," is a common symptom in those with advanced HIV disease due to a combination of factors, including metabolic changes, increased energy expenditure, and decreased food intake.

Other conditions, such as tuberculosis, rheumatic fever, or end-stage cancer, do not typically present with the same combination of symptoms. Tuberculosis may lead to weight loss and other systemic symptoms, but it would not generally cause dark purple lesions. Rheumatic fever primarily affects the heart and joints and would not cause skin lesions of this nature. End-stage cancer could potentially cause weight loss and skin changes but would more often present with a broader range of symptoms depending on the type of cancer.

Therefore, the combination of