Quick answer. Cushing’s syndrome is caused by too much of the hormone cortisol, most often from taking steroid medicines and less commonly from a tumour. It can cause a rounded face, central weight gain, purple stretch marks, easy bruising and high blood pressure – and you should never stop prescribed steroids suddenly.
Cushing’s syndrome develops when the body is exposed to too much cortisol, a hormone that normally helps regulate metabolism, blood pressure and the stress response. In Singapore the most common reason is taking corticosteroid (steroid) medicines over time for another condition; less often it is caused by a tumour that drives excess cortisol production.
The changes can build up gradually – a fuller, rounder face, weight gain around the middle, thinning skin that bruises easily, and rising blood pressure. This guide explains what Cushing’s syndrome is, its symptoms and causes, how it is diagnosed and treated, and an important safety point: prescribed steroids must never be stopped abruptly.
At a glance
| Cause | What is happening | How common |
|---|---|---|
| Steroid medicines | Long-term steroid tablets, injections, strong creams or inhalers | The most common cause |
| Pituitary tumour | A small gland tumour drives cortisol (Cushing's disease) | The commonest non-medicine cause |
| Adrenal tumour | An adrenal gland growth makes excess cortisol | Less common |
| Ectopic source | A tumour elsewhere produces a cortisol-driving hormone | Uncommon |
| Cyclical / mild | Cortisol excess that is mild or fluctuates | Can be harder to diagnose |
What is Cushing's syndrome?
Cushing’s syndrome is the collection of features that results from the body having too much cortisol over a prolonged period. Cortisol is made by the adrenal glands and is controlled by the pituitary gland in the brain. When cortisol stays too high – whether from medicine or from a tumour – it affects fat distribution, skin, blood pressure, blood sugar, bones and mood.
By far the most common cause is taking corticosteroid medicines for conditions such as asthma, arthritis or autoimmune disease. When the cause is internal, the term Cushing’s disease specifically refers to a small pituitary tumour driving the adrenal glands to overproduce cortisol. It can affect adults of any age and is more common in women.
Symptoms & signs
Features usually develop slowly and may include:
- A rounder, fuller face (sometimes called a moon face)
- Weight gain centred on the trunk, with relatively thinner arms and legs
- A fatty pad at the base of the neck and between the shoulders
- Purple or red stretch marks (striae), often on the abdomen, thighs or breasts
- Thin, fragile skin that bruises easily and heals slowly
- Muscle weakness, especially in the thighs and upper arms
- High blood pressure and raised blood sugar
- Mood changes, irritability, low mood or poor sleep
- In women, irregular periods and increased facial or body hair
Causes & risk factors
Cushing’s syndrome is grouped by where the excess cortisol comes from:
- Steroid medicines – the most common cause, from long-term corticosteroid tablets, injections, or sometimes strong creams or inhalers used over time
- A pituitary tumour (Cushing’s disease) – a usually benign growth that signals the adrenal glands to overproduce cortisol
- An adrenal tumour – a growth on an adrenal gland producing excess cortisol directly
- An ectopic source – a tumour elsewhere in the body producing a hormone that drives cortisol
The main risk factor is taking steroid medicines, which is why these should only be used as prescribed and reviewed regularly.
How it's diagnosed
Diagnosis starts with a careful review of your symptoms and medicines, then tests to confirm high cortisol and find its source:
- A review of all steroid medicines, including tablets, injections, inhalers and creams
- Tests to confirm excess cortisol – for example a late-night salivary cortisol, a 24-hour urinary cortisol, or a dexamethasone suppression test
- Blood tests including ACTH to help locate the source (pituitary, adrenal or elsewhere)
- Imaging such as an MRI of the pituitary or a CT of the adrenal glands once the type is clarified
Diagnosis can be involved, so it is usually coordinated by an endocrinologist.
Treatment options
Treatment is aimed at the underlying cause:
- If steroid medicines are the cause – your doctor will review whether the dose can be carefully reduced or an alternative used. This must be done gradually under medical supervision. Do not stop prescribed steroids suddenly, as this can cause a dangerous drop in the body’s own cortisol
- For a pituitary tumour – surgery to remove it is often the main treatment, sometimes with radiotherapy or medicines
- For an adrenal tumour – surgery to remove the affected gland
- Medicines that lower cortisol production, in selected situations
- Managing the effects of high cortisol along the way, such as blood pressure, blood sugar and bone health
With the right treatment, many features improve over time.
When to see a doctor & which specialist
See a doctor if you notice the typical changes – a rounder face, central weight gain, purple stretch marks, easy bruising or new high blood pressure – particularly if you take steroid medicines. Early assessment helps prevent complications.
Do not stop prescribed steroids on your own. Stopping suddenly can trigger an adrenal crisis with severe weakness, vomiting, low blood pressure and collapse. If someone on steroids becomes severely unwell, very drowsy or collapses, call 995. Always carry information that you take steroids and follow your doctor’s advice on dose changes and sick-day rules.
Cushing’s syndrome is managed by an endocrinologist, sometimes with a surgeon. You can find a specialist through our directory of endocrinologists in Singapore.
Living safely with steroid treatment
If your Cushing’s syndrome is related to prescribed steroids, the most important rule is never to stop them suddenly. Your body may not be able to make enough cortisol on its own, and abrupt withdrawal can trigger a dangerous adrenal crisis. Any dose changes should be gradual and supervised by your doctor.
- Carry a steroid alert card or medical identification so that anyone treating you knows you take steroids.
- Learn your sick-day rules: during illness, fever, vomiting or before surgery, you may need a higher steroid dose, so contact your doctor promptly.
- Look after your blood pressure, blood sugar and bone health, as high cortisol can affect all of these.
What to expect at the appointment
Bring a complete list of all your medicines, including tablets, injections, inhalers and skin creams, as some steroids are easy to overlook. The doctor will review these alongside your symptoms and arrange tests to confirm cortisol levels and locate the source. Diagnosis can take time and several tests, and is usually coordinated by an endocrinologist.
Costs and financing in Singapore
Specialist review, hormone tests and any imaging or surgery are available at public hospitals with subsidies for eligible patients. MediSave can usually be applied towards hospitalisation and surgery within the set limits. Ask your care team which schemes apply to your situation.
Common questions
Will the changes reverse with treatment?
Many features, such as weight gain and skin changes, often improve gradually once cortisol levels return to normal, though this can take months.
Are inhaled or skin steroids a concern?
Used as prescribed they are usually safe, but high doses over long periods can sometimes contribute. Always use them as directed and review them with your doctor.
Related guides
- Best Endocrinology & Diabetes Clinics in Singapore — our editorial shortlist
- endocrinology & diabetes clinics directory
- Myasthenia gravis
- Hyperparathyroidism
- Ovarian cancer
- Endometrial cancer
- Bartholin's cyst
Sources
- NHS – Cushing's syndrome
- Mayo Clinic – Cushing syndrome
- HealthHub Singapore
- SingHealth – Conditions and treatments
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