How is a fissure generally diagnosed?

Symptoms or exam. Classic symptoms of an anal fissure include bleeding and painful bowel movements especially after straining. A fissure can typically be diagnosed on rectal exam. Your provider should use both lubricant and Lidocaine for the exam as it can be painful.
Clinical ; exam. The most common description is if one is "passing shards of glass". Usually a physician can identify telltale signs of an anal fissure on a gentle but close exam.