how long can a cold last in a toddler?

[Deminism]

DS is 3 and has had a horrid cold for 8 days now. First day he was just off colour and refused to go swimming with his siblings. By the next day he had horrible cough and has now been snotty for about five days. No rash, slight temp, barely eating and when he does at least half the time he coughs himself sick after. He wants lots of milk (I know milk is meant to lead to mucus but it actually the only thing he can keep down). He is weeing and pooing and has several hours a day of being bright eyed and playful, and several hours of being heavy lidded and clearly ick. He is currently having a mammoth three hour and counting daytime nap (I am sitting with him and he is fine) but that is no surprise as he coughs all night so that is surely keeping him awake. HE may have lost a bit of weight with the not eating but he is a pretty chunky rugby player ish type toddler so not really that noticeable.
Oh and he had flu jab (not jab, the sniffy one) about a month ago.
So I am sure just a cold and nothing to worry about - but how long can this go on for? He is off nursery today and I took day off work because yesterday he seemed so out of it for much of the day and kept coughing himself sick.

When my DS stated nursery at 14 months, I swear he was ill from that September to maybe April/May? It was never ending, low level poorly that was so draining. Like you said, snotty, snuffly, coughs, the occasional tummy bug. He only went for two mornings a week so caught everything going and never built the immune system to fight it off! I caught everything he had too. He didn't want to do anything fun and was pretty grumpy for an awful lot of it.

He has two older siblings and is at nursery three days a week so I think probably exposed to a lot - but has actually never really been ill before. Even when half his nursery were off with chicken pox he didn't get it.

My DS has just started nursery (11mo) and has had a horrific cough/cold for 2.5weeks now and sounds very similar to your LO other symptoms!
Hoping it won’t last much longer as the poor boy is tired and grumpy but doesn’t seem unwell enough to see a GP!

My 3 year old has been sick most of the last two winters, and we have now entered another spiral of snot and coughing that will probably last until May. It is very draining, as I inevitably catch each bug from being coughed on, hugged etc.

I don't know how to break out of this cycle, and fully expect to be dead by spring, as my immune system can't take another battering.

Same as pp's my ds 4 spent last winter sick from Sept-June after starting nursery, this year seems to be going the same route only we started at end of Sept and he hasn't had quite as many fevers as last year just continuous cough/snot so I'm counting that as a small win. You said he's been ill for about 8 days, I'm afraid that's totally normal, if you look on the NHS website it says colds can last between 10-14 days particularly a heavy one and the cough can linger for up to 3 weeks afterwards. If the fever has lasted 8 days I would be inclined to have him see a gp but other than that probably normal, lots of rest, fluids, steamy bathroom, vapo rub, calpol etc xx

If I remember correctly, about 6 months, usually Oct - April. I certainly remember one particularly bad winter where I swore that, if we had to go to the doctor 1 more time, I was taking both children and going to a Mediterranean isle until spring.