Doctor's Diary: predicting the hayfever season It was intriguing to learn this week that it is now possible to predict the onset of the hayfever season, which is scheduled to start this year on March 15 in the south of the country before slowly moving northwards. This is earlier than usual, according to Professor Jean Emberlin of the organisation Allergy UK, who anticipates that the mild winter, followed by a cold spell, will triple the amount of birch pollen in the atmosphere. "The relatively high-ish soil temperatures have allowed early functioning of roots and growth of catkins," she comments. There are, of course, many different forms of hayfever, depending on which type of pollen the individual is sensitive to - but thankfully all can be treated with a selection of preventative remedies, of which the best, besides steroids, is the antihistamine fexofenadine. The one-time enthusiasm for desensitisation as a treatment for hayfever has waned in recent years, though several readers have described how exposure to high concentrations of the pollens to which they are allergic has fortuitously cured them of their symptoms. William De Stratton from Ipswich, as a teenager growing up on a farm, described how he "suffered terribly." His eyes were so swollen he could hardly see out of them, while his sneezing fits left him exhausted. On one occasion, having helped out with threshing in the barn, he was so incapacitated that he took to his bed. "The following morning, I woke with a clear head and free of symptoms," he reported, and has remained so ever since. There is, it turns out, a straightforward explanation for the "flash of lightning" that occurs when paying a nocturnal visit to the bathroom in the dark - as featured in this column last week and reported by several other readers. It is all to do with the vitreous humour, the jelly-like substance that keeps the eyeball round and bouncy. With age, this can pull away from its attachment to the optic nerve at the back of the eye and, according to ophthalmologist Mr Kenyon Jones, "tends to flop around, brushing against the retina and producing a flash of light." This is scarcely noticeable during the day but can be quite dramatic in the dark. It is usually benign but could herald the onset of retinal detachment, so it might be wise to have it checked out. This week's conundrum comes courtesy of Mrs D B from the West Midlands who, for the last couple of years or so, has been troubled intermittently by a tightening of the throat while walking that is only relieved by rest. These symptoms are suggestive of, but do not quite fit, both oesophageal spasm and angina, for which she has had the full range of possible investigations (barium swallow, endoscopy, angiogram and so on). Now, she reports, "everyone seems to have given up," and it would be reassuring at least to hear from someone similarly affected. Finally, my apologies to those (understandably) confused by a glitch in the last paragraph of my comments last week on the significant contribution of medical over-treatment to the current epidemic of diabetes. To clarify: three different types of drug for lowering the blood pressure - diuretics, ACE inhibitors and beta-blockers - together with the ubiquitous statins, can all push up the blood sugar level. The risk is small but, with these medications now so widely prescribed, the numbers affected could be substantial. There is also likely to be a ratchet effect where the prescribing of, say, a diuretic, increases the blood sugar, resulting in diabetes, which then leads to the prescribing of a cholesterol-lowering statin that pushes it up still further and so on. This is clearly a most undesirable situation about which many family doctors seem to be unaware or complacent, as they are financially rewarded for treating diabetes, however caused. There is thus every reason for those taking one or other of these types of drugs, who have then developed diabetes, to enquire of their doctor whether this may be a side-effect of their medication - and whether they need to be on it in the first place.