A Crohn's disease is an inflammatory bowel disease (IBD). It is an autoimmune condition, which means that the immune system is attacking and causing damage to the body's own tissues. Crohn's disease involves all the layers of the bowel, but it can affect any part of the gastrointestinal tract - from the mouth to the anus - whereas ulcerative colitis, another IBD, affects only the colon and rectum.
Medicine's response is basic and primitive. Steroids form the mainstay drug therapy, but they're very powerful. In particular, the immunosuppressant drug ciclosporin (which used to be spelled 'cyclosporin') can cause kidney damage, even at low initial doses (Dig Dis Sci, 1993; 38: 1624-30).
Surgery is the drastic next stage, and it's a very aggressive procedure, often removing half of the small intestine. This will certainly stop the symptoms but, like most things in medicine, it fails to address the underlying cause (Int Surg, 1992; 10: 2-8). It can also create other problems such as malabsorption and diarrhoea (Postgrad Med J, 1997; 73: 225-9).
Doctors are equally confused as to the cause of Crohn's, though it's generally agreed that genetics plays a part. If you have a current sufferer in the family, your chances of developing the condition are 3.5 to 10 times greater than someone without such a familial link (N Engl J Med, 1991; 324: 84-8).
But there the consensus ends, and there is strong evidence that points to a range of possible causes. This lends support to the theory that Crohn's disease isn't a disease at all, but a response to a range of causes that, in turn, determine the type of Crohn's you have. Find the cause and you find the key to the cure, it seems.
This suggests that you may well have to be your own medical detective, and investigate the many possible causes that come under suspicion. The most frequently mooted are viral and bacterial agents, especially the human herpesvirus 6 (HHV 6), the Epstein-Barr virus (EBV) and cytomegalovirus (CMV) (J Med Viriol, 1992; 38: 183-90).
But perhaps the front-runner of them all is Mycobacterium paratuberculosis, which is known to cause chronic enteritis in animals, and may be a reason for the genetic connection in humans. The standard pint of milk can carry this bacterium, which seems able to survive the pasteurisation process.
Dr Andrew Wakefield, now best known for his theory that the MMR (measles-mumps-rubella) vaccine may cause autism, has also posited that the measles virus - possibly originating from the vaccine itself - could play a part by restricting the blood vessels that feed the gut (Gastroenterology, 1995; 108: 911-6).
There is also a strong link to the NSAID (non-steroidal anti-inflammatory drug) family of painkillers. In one study, researchers found that 38 per cent of patients who developed an IBD did so while taking an NSAID (Lancet, 1994; 334: 1028).
Finally, consider a food allergy or intolerance. Doctors continue to emphatically rebut the possibility of such a connection, but there's plenty of evidence that suggests it should be one of the very first places to start looking.