Anal pain isnõt always due to piles; there are a number of other quite common causes.

A knife-like pain when you have your bowels open, which may last for 10-15 minutes afterwards, is probably caused by an anal fissure. You may notice some bright red blood on the toilet paper at the same time. An anal fissure is a split in the anal skin, just inside the anus, usually towards the back. You may be able to feel a small lump alongside the crack; this is a skin tag. Anal fissures are most common in teenagers and young adults, and there has often been a period of constipation beforehand. They can heal on their own, but it takes a long time and the scar often splits again.

If you think you have a fissure, smear some painkilling gel (Anodesyn, Anusol, Germaloids, Lanacane - available from your chemist) around the area just before you have your bowels open. This prevents the anus going into a spasm, which can make the problem worse. Donõt use the gel at any other time, or for more than a week, because you can easily develop an allergy to its ingredients. If you notice soreness and itching, as well as the sharp pain, it is quite likely that the gel is responsible. It is also important to avoid becoming constipated - eat lots of bran cereals, fruit and vegetables.

If the problem persists for more than 14 days, your GP may send you to the rectal clinic at your local hospital. Until recently, the usual treatment was a small operation under a general anaesthetic. This operation overcomes the spasm of the anal muscle but, though the pain relief is dramatic and instantaneous, it may leave you less able to control wind.

Instead of an operation, two new treatments are being tried out in some hospitals. One uses glyceryl trinitrate ointment, which is applied several times a day for 6 weeks. This seems to heal 60-70% of cases. The other treatment is an injection of botulinum toxin into the muscle of the anus, which seems to be even more effective.

A similar pain can be caused by herpes simplex virus, which can infect the anal area in both homosexuals and heterosexuals. At the anus, herpes often forms a crack rather than the small ulcers that tend to occur elsewhere. The soreness occurs in episodes, each lasting for a few days. A genitourinary medicine clinic will be able to take a swab to check for the virus if you visit the clinic as soon as an episode starts.

A nagging, aching discomfort made worse by defecation could be due to piles (see Piles).

A throbbing pain, worsening over a few days, and bad enough to disturb your sleep, is likely to be caused by an abscess. You may be able to feel a tender swelling in the skin close to the anus, or the abscess may be hidden inside. This is unlikely to go away on its own; it needs to be lanced by a doctor, so see your GP for this simple procedure.

An occasional, severe, cramp-like pain deep in the anal canal, lasting about half an hour is probably a condition called proctalgia fugax. It is a mysterious condition, and usually affects middle-aged men; no one knows what causes it. The pain often wakes sufferers at night, and men may have an erection at the same time. The pain goes away of its own accord, and there are no other effects. The best treatment is to take 2 paracetamols and a hot drink, and hope that it wonõt happen again.

A continuous aching pain in the anus needs to be sorted out by your doctor. It is most often caused by a back problem (when a part of the spine presses on a nerve).