GCXZ

It has emerged that this devastating if eminently treatable condition, now renamed Bile Acid Diarrhoea, is more prevalent than supposed, and may be a complicating factor of several bowel disorders. Thus, typically, a lady from Bath diagnosed as having ulcerative colitis more than 30 years ago reports how she still suffers bouts of such severity that she's become reluctant to venture out. Her husband discovered there is now a special test, known as SeHCAT, that measures the loss of bile acids from the gut, which turned out in her case to be abnormal. "I don't usually believe in miracles – but this is one," she writes.

The conundrum of whether the tendency of the lady who says things "that are inappropriate" might be related to her anti-migraine drug Zolmitriptan has prompted another reader to describe becoming very aggressive within an hour of taking a similar medication. "I now have to tell my family when I have taken the drug so they know to ignore my outbursts."

This would suggest that anti-migraine drugs, in some, have these kind of adverse psychological effects, were it not that paradoxically they are known to reduce rather than exacerbate aggressive tendencies. Indeed, psychiatrists in Norway are investigating their efficacy in a group of aggressive criminals, whose members are "resistant to conventional pharmacological and psychological treatment". This raises the possibility that it might be the migraine, rather than the medication, that is responsible.

Mystery eye

This week's medical query comes courtesy of Mrs AN from Surrey, troubled with grittiness of the left eye, treated by her family doctor with an antibiotic cream. Then, bizarrely, a few days later, "a thin black object, like a rigid hair" is extruded from the eye and her symptoms resolve – until the next time. What, she asks, could be responsible?

Moisturiser warning

Finally, further to the comments implicating those brands of toothpaste containing sodium lauryl sulphate (SLS) as a cause of recurrent mouth ulcers, it now appears that the same chemical in aqueous cream, the widely prescribed soap substitute, can exacerbate the cracked and itchy skin of eczema. "My husband's hands would become red and split at the knuckles," writes a reader. It would seem that prolonged contact of the SLS chemical with the skin, when aqueous cream is used as a moisturiser (for which it is frequently prescribed), can worsen eczema – especially in children. It can, however, still be used as a soap substitute as long as it is promptly washed off.

Email medical questions confidentially to drjames@telegraph.co.uk. Answers will be published every Friday, at telegraph.co.uk/health