Do I have a food allergy? How can I stop cystitis attacks?

Is food making me ill?

Is it possible to have a mild food allergy that only brings on symptoms intermittently? I sometimes develop a runny nose and itchy throat soon after eating certain foods. The symptoms are mild and don't really trouble me, but it would be nice to know what causes them.

Allergies of all kinds are becoming more common in the UK. It may be because our environment is becoming cleaner. Without regular contact with germs, the body may be more likely to react to certain foods. A reaction that consists of a runny nose and an itchy throat definitely sounds allergic. There are cells in the throat and nose called mast cells. When these cells become sensitised to certain foods, they secrete chemicals such as histamine which cause the unpleasant symptoms. You could have some specialised allergy tests to find out the exact cause of the reaction. But if the symptoms are mild and not troublesome, it's not worth worrying about them. A severe food allergy will cause tongue swelling, wheezing and difficulty in breathing. This is a medical emergency that needs urgent treatment in a casualty department.

Cystitis hell

Cystitis is beginning to rule my life. I have had at least four attacks in the past year, and the most recent was the worst. For 24 hours, I was passing more blood than urine. I drink cranberry juice until it is coming out of my ears, and I have had a kidney and bladder scan, which did not show anything wrong. Antibiotics always solve the problem, but I usually have to endure a couple of days of agony before I can get a prescription. Is there some way of preventing cystitis? Sometimes it happens after I have sex.

Cystitis is caused by an inflammation or infection in the bladder. Most cases of cystitis occur in women and this is because the design of women's urethra and bladder makes it relatively easy for bacteria to get into the bladder. It usually starts off as some minor discomfort and burning sensation as you pass urine. If it gets bad, and the bladder wall gets very inflamed, the urine turns bloody. Untreated cystitis can develop into a serious kidney infection. If the scans are normal, you should ask your doctor for an emergency supply of antibiotics so that you can start taking them at the first sign of symptoms. I know some women who can only prevent cystitis if they take a dose of antibiotics immediately after having sex.

Please send your questions and suggestions to A Question of Health, 'The Independent', 191 Marsh Wall, London E14 9RS or e-mail Dr Kavalier regrets that he is unable to respond personally to questions

Readers write

JK from Surrey prevents subconjunctival haemorrhages by avoiding certain foods: I have been suffering from eye haemorrhages for years. By trial and error, I have found that wheat gluten is the cause of my problem. By excluding this from my diet, I am able to keep my eyes 'red'-free. One problem is that wheat additives are found in many processed products, even some yogurts.