Charity Oscar Birmingham says the cold leads to painful sickle cell flare-ups and hospital stays.
The soaring cost of living will lead to an increase in hospital admissions for people with sickle cell this winter, a charity has warned.
The condition, which affects red blood cells, means people must keep warm to avoid painful flare-ups which can often lead to a hospital stay.
One Birmingham family said they were staying in bed to keep warm as energy bills rise.
Charity Oscar said 89% of its clients were anxious about heating costs.
Joana and her 12-year-old son Steven, from Selly Oak, in Birmingham, both have sickle cell disease.
She said she had about £900 a month to live on and used small electric heaters to warm individual rooms, plus extra layers of clothing, to avoid putting the central heating on.
“When the house isn’t warm, that triggers the pain so much more,” she said. “Winter time is the worst. I always have to put layers of clothes on, like leggings, before my jeans.”
Steven said: “If I get cold, I feel a bit weird, I get chest pains and belly aches. We can’t use any heaters, it wastes too much energy. Instead we just cover up, or stay in bed.”
Oscar Birmingham, Organisation for Sickle Cell Anaemia Relief and Thalassaemia Support, works to improve the health, social and economic wellbeing of those with the disease.
Hobby Rahman, from the charity, said: “If they fail to keep their homes warm sufficiently, that will trigger off a crisis, resulting in more children admitted into hospital, more pressures on the NHS.”
People with sickle cell disease produce unusual sickle-shaped red blood cells which can block blood vessels. It can cause chronic pain, especially when exposed to colder temperatures.
It is a genetic condition and is particularly common in African and Caribbean communities.
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