Cushing's Syndrome
Cushing's syndrome is chronic excess cortisol exposure, either from a tumor producing it or from long-term steroid medication, evaluated per the Endocrine Society’s treatment Clinical Practice Guideline.
Symptoms
Weight gain (especially central and facial), thin skin that bruises easily, purple stretch marks, muscle weakness, high blood pressure, and elevated blood sugar -- the combination is what raises suspicion, not any single finding.
Causes and risk
A pituitary tumor (Cushing's disease) is the most common endogenous cause; ectopic ACTH-producing tumors and adrenal tumors are less common, per a 2024 disease-primer review. Long-term steroid medication for another condition is the most common cause overall.
How it is evaluated
Three first-line screening tests -- 24-hour urine free cortisol, late-night salivary cortisol, and the 1mg overnight dexamethasone suppression test -- remain the standard framework, per Endocrine Society/Pituitary Society diagnostic recommendations.
Treatment
Surgery to remove the source of excess cortisol (pituitary or adrenal) is first-line when feasible; medication that lowers cortisol production is used when surgery isn't possible or as a bridge to surgery, per the Endocrine Society guideline.
When to seek care
The Endocrine Society guideline calls for urgent treatment within 24-72 hours when life-threatening complications appear -- serious infection, blood clots, cardiovascular events, or acute psychosis -- since cortisol excess can mask the usual warning signs of serious infection. Abruptly stopping long-term steroid medication can also trigger adrenal insufficiency and should never be done without medical guidance.