Alarmed, I raced home to find some anti- histamine as it was clear he had suffered an allergic reaction to something. But the most worrying aspect was I had no idea what could have triggered it.
Diagnosed at seven with anaphylaxis to nuts and an allergy to sesame seed, we spent his childhood on tenterhooks whenever he went on a play date or party.
Having experienced a few episodes where he appeared to become wheezy and itchy for no apparent reason, we took him to our GP who referred us to an allergy specialist, where after much insistence on our behalf, we got him tested for hazelnut, which isn't on the main list of common allergies, but we had a suspicion that he might be allergic to it. It was extremely fortunate that we insisted because although the consultant wanted to send us away with a diagnosis of a sesame allergy, our perseverance revealed that he had, in fact, a severe anaphylactic aversion to hazelnut.
The initial shock at this diagnosis gave way to fear as we realised how serious the situation was. We were told that anaphylaxis can be fatal if not dealt with immediately and we would have to carry an Anapen (a shot of adrenaline) with us at all times in case of emergency. All food had to be vetted for traces of nuts or seeds and every label would have to be scrutinised.
It seemed like a sentence -- having survived the previous years by the skin of his teeth, we were now horrified by the possibility that even the trace of an innocent nut could have fatal consequences.
We felt completely daunted by the severity of his condition. But now, seven years later, we are older, wiser and calmer. We know that by shopping with care and making sure that nothing containing nuts comes into the house, Cailan can enjoy a normal life. Having said that, there have been times when I have been lax about the rules.
On one particular occasion, a packet of biscuits was doled out at a friend's house and I allowed him to have one without checking the ingredients. Within seconds, he felt sick and I could hear his throat beginning to swell. Minutes later, he was sick.
This episode really brought me to my senses -- to witness how quickly the allergen can take affect made me realise I just can't be relaxed about this situation -- ever.
So it has become a way of life for us -- we don't leave the house without the adrenaline pen, everyone has been warned to keep him away from nuts and because he is aware of how awful even the mildest reaction can be, Cailan is careful to avoid anything that looks suspicious.
But the onset of adolescence has brought a whole new set of worries. He has moved out from under my watchful gaze, is eating out with his friends and meeting new people. And being the stereotypical teen does not want to alert his peers to his strange affliction unless absolutely necessary.
Which brings me to the basketball incident -- an hour after taking the antihistamine, the swelling on his face and torso finally began to subside and after racking our brains, we realised the only unusual ingredient he had eaten that day was cardamom, added to some home-made buns.
We had no idea this spice was problematic and this opens up a new level of fear.
Could there be other ingredients which he is unwittingly allergic to? How will he get through the next few years without eating something which will cause him to have a reaction? How are we going to deal with this?
At the moment, all I can do is talk to him and be on constant alert. It might sound harsh but I have to tell him about the reality of what could happen if he were to ingest a nut and no one was there to help him or if he ate an ingredient which he hasn't eaten before.
I purposefully discuss his anaphylaxis in front of his friends, because I will be counting on them to help him.
And, apart from instilling in him the gravity of the situation, I am powerless to do anything else and this really scares me.
Last year, Laura Kukic, a 14-year-old girl from Bedfordshire in England, was rushed to hospital after 'the kiss of death'. Dangerously allergic to nuts, the teenager gave her 16-year-old boyfriend a peck on the lips as she passed him in the school corridor.
But she was unaware of the fact that he had eaten cereal containing hazelnuts for breakfast and despite brushing his teeth several times before school, the quick kiss caused her to collapse with anaphylactic shock.
Fortunately, she survived to tell the tale and this is one bedtime story that my son needs to pay heed to as the happy ending will only take place if he makes it happen.
The latest research has shown that by introducing small amounts of the allergen into the system, the body may eventually become accustomed to it. And scientists are even hoping to develop a nut that is allergy free.
Professor Jonathan Hourihane is one of the leading allergy specialists in the country. He said: "Studies have shown that tolerance levels can be built up gradually in some cases, but even the groups doing the trials say treatment options are not ready for clinical use right now. There are too many unknowns for this to be part of a treatment plan at present -- but we are hopeful for the future."