Can’t lose weight and constantly feel cold? It might be down to an ‘invisible illness’ that can be reversed

PUTTING on weight and feeling cold all the time can feel inevitable in winter — but they may be signs of an “invisible illness”.

The sickness can also leave you feeling tired and depressed, experts say.

GettyBeing sensitive to the cold or struggling to lose weight are signs of an underactive thyroid, according the NHS[/caption]

All four are symptoms of an underactive thyroid, where the gland does not produce enough hormones.

The condition can be treated by taking daily hormone tablets but is not always easily spotted.

An NHS spokesperson said: “Symptoms of an underactive thyroid are often similar to those of other conditions, and they usually develop slowly, so you may not notice them for years.

“For example, if you are at an age where you may be expecting the menopause, you may think you have started the menopause rather than having an underactive thyroid.”

Some 2.2million Brits are thought to be living with an underactive thyroid, according to the National Institute for Health and Care Excellence (NICE).

The illness is caused by the immune system attacking the thyroid gland and damaging it, making it produce less of the hormone thyroxine.

It can also be caused by damage caused by treatments for thyroid cancer or an overactive thyroid.

Without treatment, the condition can increase your risk of heart disease because low levels of thyroxine can increase levels of cholesterol in the blood.

An underactive thyroid can also lead to goitres — swellings of the thyroid gland that cause a large lump in the throat.

If left untreated during pregnancy, it can increase the risk of preeclampsia, anaemia in the mother, birth defects, premature birth and more.

In rare cases, an underactive thyroid can lead to a life-threatening condition called myxoedema coma.

According to the NHS, the only accurate way of finding out whether you have a thyroid problem is to have a blood test that checks hormone levels.

You should see a GP and ask to be tested for an underactive thyroid if you are suffering tiredness, weight gain, depression, cold sensitivity, dry skin and hair or muscle aches.

Most patients are given daily hormone replacement tablets called levothyroxine if they test positive.

Doctors perform blood tests over several weeks to determine the right dose of the drug and it is usually taken for the rest of your life, as an underactive thyroid is a lifelong condition.

While the condition cannot be cured, the signs and symptoms of an underactive thyroid can be totally reversed with the drugs.