Benign Prostatic Hyperplasia (BPH): This condition is common in older males and can cause microscopic or gross hematuria due to prostate enlargement and its effects on the urinary tract. The absence of pain and infection, along with the presence of hematuria, makes BPH a plausible diagnosis.

Kidney Stones: Although pain is a common symptom, some kidney stones may not cause significant discomfort, especially if they are small and not obstructing the urinary tract. Hematuria is a common finding in patients with kidney stones.
Urinary Tract Malignancies: Cancers of the bladder, kidney, or prostate can present with hematuria as an initial symptom. The absence of pain or infection does not rule out these conditions, as they can be asymptomatic in their early stages.
Nephrological Conditions: Conditions such as IgA nephropathy or thin basement membrane disease can cause recurrent hematuria without significant pain or infection.

Renal Artery Aneurysm or Arteriovenous Malformation: These vascular abnormalities can cause hematuria and are critical to diagnose due to their potential for severe complications, including rupture and hemorrhage.
Sickle Cell Disease or Trait: In patients with sickle cell disease or trait, hematuria can occur due to sickling in the renal medulla. This condition is important to identify due to its implications for management and potential complications.
Renal Vein Thrombosis: This condition can cause hematuria and is particularly important to diagnose in patients with risk factors such as nephrotic syndrome or dehydration, as it can lead to severe renal damage if not promptly treated.

Goodpasture Syndrome: An autoimmune disease that can cause hematuria due to anti-GBM antibodies. It is rare but important to consider due to its potential for rapid progression to renal failure and pulmonary hemorrhage.
Alport Syndrome: A genetic disorder affecting the type IV collagen in the glomerular basement membrane, leading to hematuria, hearing loss, and eye abnormalities. It is rare and often diagnosed in younger patients.
Nutcracker Phenomenon: A condition where the left renal vein is compressed between the aorta and the superior mesenteric artery, potentially causing hematuria. It is a rare cause of hematuria but should be considered in patients with unexplained left renal vein thrombosis or hematuria.