Cushing's syndrome

What it means

The NIDDK says the most common cause is long-term use of high-dose glucocorticoid medicines, which act like cortisol and are prescribed for conditions such as asthma, rheumatoid arthritis and lupus. Less often, a tumor makes too much cortisol or the hormone that drives it.

Signs can include weight gain with a rounded face, fat at the base of the neck and between the shoulders, thin arms and legs, wide purple stretch marks, easy bruising and muscle weakness. High blood pressure and high blood sugar are common.

When the body makes too much cortisol on its own, the condition is rare, with estimates of roughly 40 to 70 cases per million people.

Diagnosis uses blood, urine or saliva tests and sometimes imaging. Treatment depends on the cause. Never stop a prescribed steroid suddenly, because that can be dangerous; your prescriber can plan a safe taper if one is needed.

Why it matters

Unexplained weight gain with these signs is worth checking, since treating the cause matters more than any diet.