Not all cases of allergy are as straightforward as the recent unfortunate case of a woman who died of an allergic reaction after eating prawns (Woman with allergy dies after eating prawns; Aug 22).

Years back, I had a near-death experience in China after a teppanyaki meal of prawns and other seafood.

I broke out in hives and was choking, as my tongue was rapidly swelling. I could not speak and was suffocating. My timely admission to hospital saved my life.

Not long after, I had a second attack in Singapore, which came about after a meal of fried prawn noodles. Again, a timely admission to hospital saved me.

I was convinced the culprit must be prawns. My allergy tests, although not quite conclusive, alluded to it as well.

But I could not reconcile this with the fact that I could still take prawn soup, dried prawn sambal, crayfish, crabs and lobsters without so much as a hint of a reaction.

Determined to investigate, at my own risk, I ate nine steamed prawns which had been bought live, and waited. My wife was armed with an EpiPen and was ready to have me hospitalised at the first sign of trouble. But nothing happened.

Months later, I tried again, this time with some wild sea prawns, after confirming with the vendor that these were wild-caught and not farmed. Again, nothing happened.

Unscientific as it may be, I concluded that I am not really allergic to crustaceans, least of all prawns. I believe that the source of the prawns made the difference.

I was told that the feed for farmed prawns is usually concocted by farmers, who use certain antibiotics to safeguard their stock.

My allergy to tetracycline and sulphur-based antibiotics could possibly be the link.

Prawns are a favourite food item among the people in Singapore.

Perhaps the Health Ministry could investigate and help determine the causes of prawn allergies and allay unnecessary fear among allergy sufferers.

The authorities could also issue advisories to farmers on the risks of using antibiotics or other treatments that could pose a hazard to unsuspecting consumers.

Anthony Ng Seet Boo