All my parts had been in fine working nick when I switched off the light the night before, but seven hours later it was down to all but one. I could put it less discreetly, but let's just say my willy had turned the colour of a raspberry lollipop. It certainly did not look like a happy member and didn't feel too wonderful either.

Without a word to anyone I snuck off to the GP, feeling both trepidation and embarrassment. He made a cursory examination before suggesting it "may be some sort of VD" and that a visit to the local Sexual Health Clinic would be in order. After a moment's silence he inquired whether I'd been "sleeping around" without a condom. "No!", I answered indignantly. "Well then," he said with a knowing look on his face, "if I were you I would have a word with my wife."

I huffed home for a full-blooded confrontation, but was met with an amused response. "Sounds just like thrush - and by the way you didn't get it from me," my wife said. "Can't be thrush," I snapped back, "that's a girl's thing!"

After two hours in the clinic queue, desperately trying to avoid the eye of any of the other unfortunates, I was seen by a buoyant young medic, who had a look, took a scrape of surface cells, and 10 minutes later bounced back and told me it was nothing serious. "Just a mild case of thrush."

He explained the ailment was medically known as candidiasis, and that, contrary to my prejudices, it was not just a female phenomenon. "For some strange reason, our male patients assume it only affects women, babies and horses' hooves."

A quick quiz followed: did my partner have it? (no); was I depressed? (no); did I wash under my foreskin (absolutely, yes); nylon undies? (absolutely not); cycle a lot? (yes). "That'll be it then. Warm weather, long spells on the bicycle seat and too-tight knickers. My advice is to get that dick out into the cool fresh air, always wear cotton and never anything too tight."

He handed me a tube of anti-fungal cream and assured me the infection would be vamoosed in a day or two - which indeed it was. And so, my first and last dose of a condition that doctors fondly call "spotted dick" and that causes unnecessary alarm among tens of thousands of British men each year, was over. As another doctor put it: "Women know what it's all about and take it in their stride, but men! You know what men are like about their bits. They tend to get extremely alarmed."

Thrush is not a venereal disease but is caused by Candida albicans, a fungus carried by everyone, which thrives in warm, moist conditions - commonly in the vagina but also under the uncircumcised male foreskin. Although the infection can be passed on by sex, it is often associated with other factors, especially the use of antibiotics, some of which destroy the bacteria that normally control the fungus. It is also more likely to occur when the body's immune levels are low - either naturally (which is why depression can contribute) or as a result of steroid treatments used, for example, in asthma.

In men, symptoms include red spots or an inflamed penis tip, inflammation and itching, and an increase in white, curd-like smegma under the foreskin. For a couple of days sex is out of the question and, in more severe cases, even walking may be uncomfortable.

The good news is that thrush responds quickly to treatment and is nothing that a saline bath, a pair of cotton briefs, and a tube of anti- fungal cream (usually Canesten, now available without prescription) won't clear up. The bad news is that it often reappears when the predisposing conditions recur - in my case a combination of sunshine, sweaty exercise and an uncircumcised penis.