Image copyright Asthma UK Image caption Oscar has been in hospital 57 times with his asthma

Five-year-old Oscar's life has regularly hung in the balance because of severe asthma.

On his second birthday, he was so ill he did not respond to any medicines, leaving his parents fearing the worst.

"I will never forget how his tiny chest rose up and down in desperate movements, trying to fill his lungs with air," his mum, Carla, says.

After 57 emergency trips to hospital with her son, Carla is used to the routine but she never stops worrying.

"Within 30 minutes, he can go from coughing and looking OK to constantly coughing and gasping for breath...

"What we have been through, it's very distressing," she says.

"We've been told there's nothing else they can do for him."

Image copyright Asthma UK Image caption Oscar is now at school which means he has to be closely supervised

According to Asthma UK, it is difficult to know how many life-threatening asthma attacks happen every day in the UK, because not everyone seeks treatment for them and they can be difficult to define.

But they estimate that someone in the UK has an attack every three seconds and many of those could be avoided if people heeded the warning signs and sought help quickly.

This was based on asking 10,000 people with asthma to report how many attacks they had suffered in the past year.

Asthma is a long-term condition which affects the airways - the tubes that carry air in and out of the lungs - causing them to narrow and making it harder to breathe.

It affects 4.3 million adults and 1.1 million children in the UK.

Last year, 77,855 people were admitted to hospital with an asthma attack - and 1,250 died, around three people a day.

Most of those are older adults, the charity says, who may not pick up the signs and ask for help.

Asthma UK says you are having an asthma attack if:

your blue reliever isn't helping, or you need to use it more than every four hours

you're wheezing a lot, have a very tight chest, or you're coughing a lot

you're breathless and find it difficult to walk or talk

your breathing is getting faster and it feels like you can't get your breath in properly

The charity offers health advice on its website and has emergency advice to follow when having an asthma attack - for adults and children.

Image copyright Getty Images Image caption There can be a spike in asthma attacks over winter, linked to coughs and colds

It says the best way for people to stay well with asthma all year round is to take their preventer inhaler every day, so that protection in the airways is built up over time.

Dr Sam Walker, director of research and policy at Asthma UK, says: "Asthma attacks can be really frightening but some people don't seek help, despite advice to do so.

"But people never think it's as bad as it is," she says.

She says there can be a spike in asthma attacks over winter, linked to coughs and colds, but triggers vary from person to person, and can include pollen.

'Helpless feeling'

In Oscar's case, the symptoms are usually obvious, to the extent that he can now tell his mum when he is having an attack.

But he can deteriorate very quickly and now he is at school, the family are putting their trust in someone else spotting the signs and acting fast.

The constant worry has taken its toll on everyone, including Oscar, who sees a psychologist because of the trauma of so many hospital visits and procedures.

"I'm worrying all the time," says Carla.

"Is the school going to ring me? Should I go out?

"We can't go on holiday abroad because we need to be near a hospital and we've lost thousands of pounds on cancelled trips because he was just too poorly to go."

But the worst feeling is helplessness, she says.

"He can be coughing all night but there is nothing you can do."