An anal fissure is a small tear in the skin of the anus that can be caused by passing a large or hard poo.
Symptoms of an anal fissure can include:
a severe, sharp pain when doing a poo
a burning or gnawing pain that lasts several hours after doing a poo
rectal bleeding – you may notice a small amount of blood on the toilet paper after you wipe
Anal fissures can be very painful, but many heal on their own in a few weeks. Increasing the amount of fibre in your diet, drinking plenty of fluids and taking laxatives and over-the-counter painkillers can help.
If the pain persists, you may need special ointment that relaxes the ring of muscle around your anus. Occasionally, surgery may be needed to help the fissure heal.
An anal fistula is a small tunnel that develops between the end of the bowel and the skin near the anus. It's usually caused by an infection near the anus resulting in a collection of pus (an abscess).
Symptoms of an anal fistula or abscess can include:
a constant, throbbing pain that may be worse when you sit down