What illness would cause a person to smell bad?

Certain illnesses can lead to body odor changes. For example, conditions like Diabetes can cause a fruity smell due to ketoacidosis, while liver or kidney disease may result in a foul odor due to the body's inability to filter toxins effectively. Additionally, infections or skin conditions like bacterial or fungal infections can produce unpleasant smells. Lastly, metabolic disorders, such as trimethylaminuria, can cause a fishy odor due to the body's inability to break down certain compounds.