Cushing's syndrome explained: symptoms and treatment

What Cushing's syndrome is

Cortisol is a hormone made by the adrenal glands, which sit on top of the kidneys. In the right amounts it helps the body handle stress, control blood sugar, manage blood pressure and dampen inflammation. Cushing's syndrome is what happens when there is too much cortisol acting on the body over a long time. By far the most common cause is taking steroid medicines, such as tablets or high-dose inhalers or creams used for conditions like asthma, arthritis or inflammatory disease — this is sometimes called steroid-induced or exogenous Cushing's. Less commonly, the body itself makes too much cortisol, either from a small tumour in the pituitary gland that drives the adrenals (called Cushing's disease), a tumour in an adrenal gland, or, rarely, a tumour elsewhere. Identifying the cause is central to treatment.

The symptoms it causes

Excess cortisol produces a recognisable pattern, though it develops gradually. Common features include weight gain, particularly around the tummy, the upper back and the face, which can become rounder — sometimes described as a moon-shaped face — while the arms and legs may look relatively thin. The skin often becomes thin and bruises easily, and reddish-purple stretch marks can appear on the tummy, thighs or arms. Many people notice muscle weakness, especially getting up from a chair or climbing stairs, tiredness, and mood changes such as low mood, anxiety or irritability. High blood pressure and raised blood sugar or diabetes are common, and bones can weaken over time. In women there may be extra hair growth and changes to periods. Because these features overlap with everyday problems, the diagnosis is often not obvious at first.

How it is diagnosed

The first step is usually to review any steroid medicines, since these are the commonest cause and the picture may fit their use. If the body is thought to be overproducing cortisol, tests measure how much cortisol is present and whether it follows its normal daily rhythm — cortisol should be high in the morning and low at night, and in Cushing's this pattern is lost. Tests may include measuring cortisol in urine collected over 24 hours, in saliva taken late at night, or checking whether a small dose of a steroid switches cortisol off as it should; in Cushing's it does not. If overproduction is confirmed, further blood tests and scans of the pituitary or adrenal glands help find the source. These tests can be complex and are usually guided by hormone specialists to reach the right answer.

How it is treated

Treatment depends entirely on the cause. When steroid medicines are responsible, the answer is to review them with the prescriber and, where possible, reduce to the lowest effective dose or find alternatives — but steroids taken for a while must never be stopped suddenly, as this can be dangerous; they are lowered gradually under medical guidance. When the body is overproducing cortisol, treatment aims to remove or control the source: surgery to remove a pituitary or adrenal tumour is often the main treatment and can be curative, sometimes followed by radiotherapy or medicines that lower cortisol if needed. Alongside tackling the cause, the linked problems — high blood pressure, diabetes, weak bones and mood changes — are managed. Care is usually led by hormone specialists, and treatment is tailored to the individual.

Living with and recovering from Cushing's

Recovery from Cushing's syndrome takes time, and how it unfolds depends on the cause and treatment. When excess cortisol is corrected, many symptoms improve over months — weight, skin, mood and blood pressure often settle — though some changes can take longer or only partly reverse. After surgery to remove a cortisol-producing tumour, the body's own cortisol production can be low for a while, so hormone replacement and careful monitoring are needed until it recovers, and people are given clear advice about this. Anyone taking or recently taking steroids long-term should carry a steroid card and know the sick-day rules for illness, and should never stop steroids abruptly. Long-term follow-up checks that cortisol levels stay right and that related conditions such as bone health, blood pressure and diabetes are well managed, supporting a good recovery.