Your health questions answered

NEVER MIND THE ANTIBODIES

Q. Twenty-eight years ago, when I was pregnant with my second child, the hospital forgot to give me a rhesus injection and I developed rhesus antibodies because my blood group is A negative and my husband's is A positive. Will these ever have any effect on my health?

A. Women who have a rhesus-negative blood group develop antibodies against the rhesus proteins if they become pregnant with a baby who is rhesus positive. This does not usually cause any problems for the baby in the first pregnancy, but if they become pregnant a second time, the antibodies in the mother's blood can attack the baby's red blood cells with devastating effect. All rhesus-negative pregnant women are now given an injection to prevent them from developing these antibodies. If you were not given this when you were pregnant with a rhesus-positive baby, then your body will have produced antibodies that could have caused serious problems in a future pregnancy. But, luckily for you, rhesus antibodies floating around in your blood will not cause you any problems unless you have any more children (which sounds unlikely, if your oldest child is now 28). Rhesus injections (known as anti-D injections) were first introduced in 1968.

WRITE ON

Q. One of my flatmates at university frequently demonstrates to us an amazing phenomenon. If you take a blunt object, such as a chopstick, you can write her name on the skin of her back. Within a few seconds, the name begins to turn red and the skin then swells up wherever something has been written. She can parade around the flat for hours, with her name emblazoned in the skin of her back. When I try the same on my back, nothing happens. Why is her skin so special?

A. Your flatmate has dermatographism, which is a skin response to physical pressure. The rash that appears is similar to the rash that occurs when you come into contact with nettles. Nettle rash is caused by a chemical contained in the plant. Dermatographism is caused by the pressure of the chopstick on the skin. About 2-5 per cent of the population has dermatographism. It is a form of urticaria, which is a family of conditions that cause skin rashes. People who have urticaria tend to develop raised, itchy red rashes in response to a variety of stimuli. Sometimes the stimulus is chemical, as with nettle rash. But some people will respond in the same way to simple physical pressure on the skin. The redness is caused by the release of the chemical histamine.

TIME FOR THAT PROSTATE CHECK

Q. I think I may have a serious problem with my prostate or testes, as there appears to be blood in my semen. I am not in discomfort, and my testes seem normal. I have not yet seen my GP. What might be causing this? I am a pretty healthy 74-year-old.

A. Blood-stained semen (the medical name for this is haematospermia) is a frightening symptom that makes men worry about both cancer and sexually transmitted diseases. When younger men get haematospermia, it does not usually mean anything sinister, unless there are other symptoms such as pain or a discharge from the penis. The cause is usually a small blood vessel that bursts, leaking blood into the seminal fluid before it is ejaculated. Urologists have followed up men with intermittent blood-staining of the semen for many years and in the vast majority of cases it is not associated with any disease. But in a man of your age, there could be a more serious cause, such as prostate disease or even prostate cancer. You should see your GP for a check-up and examination. Your prostate should be examined and you probably should have a PSA test to look for signs of prostate cancer. You will probably end up by seeing a urology specialist.

Please send your questions and suggestions to A Question of Health, 'The Independent', Independent House, 191 Marsh Wall, London E14 9RS; fax 020-7005 2182; or email health@independent.co.uk. Dr Kavalier regrets that he is unable to respond personally to questions.

Readers write

The postbag and email inbox are bursting with complaints from people who resent my suggestion that the typical gout sufferer is "an overweight male who probably drinks more than he should". In my defence, I can only quote the opening sentence of last week's article: "Everyone thinks gout only affects bloated alcoholic men, but it's not true." Here's what you said:

JC emails: "I really must take issue with your comments on typical gout sufferers being overweight males who probably drink more than they should. As the Arthritis Research Council says, 'The old adage that simply eating and drinking too much causes gout has now been proved wrong.' My husband suffers from gout, as did his father before him. He is certainly not overweight, and does not overindulge in the red wine."

DH writes: "I suffer from gout. I find it extremely misleading and dangerous for this - 'A typical sufferer is an overweight male who probably drinks more than he should' - to be written in today's column about the gout sufferer. This is a stereotype. Stereotyping is a very dangerous practice, and should never be used."

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