Cushing’s syndrome is a clinical condition characterized by prolonged exposure to inappropriately high levels of glucocorticoids, most notably the hormone cortisol. While many people associate this syndrome with tumours of the pituitary or adrenal glands, the most prevalent cause in the United Kingdom is actually the use of exogenous medications. When a person takes certain types of pharmaceutical treatments for other health conditions, the level of synthetic steroids in their bloodstream can rise far above what the body naturally produces. This results in the classic physical and metabolic changes of Cushing’s syndrome even when the adrenal glands themselves are structurally normal and free of tumours. Recognizing the role of medication in this process is vital for ensuring that patients receive the correct management and that their hormonal balance is restored safely.
What We’ll Discuss in This Article
- The role of oral glucocorticoids as the primary cause of medication induced Cushing’s.
- How non oral routes such as injections and creams can contribute to the condition.
- The interaction between common medications and the body’s natural cortisol production.
- The risks associated with high dose or long term steroid use for chronic conditions.
- How medication induced Cushing’s differs from tumour based causes.
- The process of tapering medication to resolve symptoms of excess cortisol.
Oral Glucocorticoids and Hormone Excess
The most frequent medical cause of Cushing’s syndrome without an adrenal tumour is the long term use of oral corticosteroid tablets. Medications such as prednisolone, dexamethasone, and hydrocortisone are powerful anti inflammatory drugs used to treat a wide range of conditions, including asthma, rheumatoid arthritis, and inflammatory bowel disease. These drugs are designed to mimic the action of natural cortisol, but at the doses required to suppress severe inflammation, they often exceed the body’s physiological requirements.
According to the NHS information on Cushing’s syndrome, taking these tablets for more than a few weeks can lead to the development of symptoms such as a rounded face, weight gain around the midsection, and thin, fragile skin. Because the source of the hormone is external, this is referred to as exogenous Cushing’s syndrome. In this scenario, the adrenal glands are not the source of the problem; in fact, they often become inactive and shrink because the high levels of medication signal the brain to stop stimulating natural hormone production. This is a critical distinction, as the treatment focuses on adjusting the medication rather than performing surgery on the glands.
Impact of Injected and Inhaled Steroids
While oral tablets carry the highest risk, Cushing’s syndrome can also be triggered by other forms of steroid administration. Steroid injections, often used to treat localized joint pain or inflammation in the back, deliver a concentrated dose of glucocorticoids directly into the tissue. If these injections are administered too frequently or in high doses, enough of the medication can enter the general bloodstream to cause systemic symptoms of hormone excess. Medical guidelines in the UK typically suggest limiting the number of joint injections a person receives in a single year to minimize this risk.
Inhaled steroids used for asthma or chronic obstructive pulmonary disease (COPD) are generally considered safer because they are targeted at the lungs. However, at very high doses, a small amount of the drug is absorbed through the lining of the lungs and into the blood. Over a long period, this cumulative absorption can lead to mild signs of Cushing’s syndrome, particularly in children or older adults who may be more sensitive to the medication. Similarly, potent steroid creams used for severe skin conditions like eczema or psoriasis can cause problems if applied to large areas of the body or used under bandages, which increases the amount of drug that penetrates the skin.
Drug Interactions and Adrenal Suppression
Certain medications can increase the risk of Cushing’s syndrome by interfering with how the body breaks down steroids. For example, some antifungal medications and treatments used for HIV can inhibit the enzymes in the liver that normally clear steroids from the system. If a patient is taking a low dose of a steroid alongside one of these “potentiating” drugs, the steroid can build up in the body to dangerous levels, leading to the sudden appearance of Cushing’s symptoms.
This interaction is particularly concerning because it can also lead to a secondary problem known as adrenal suppression. While the patient has too much steroid in their system, their natural adrenal glands have completely shut down. If the medications are stopped suddenly, the patient can fall into a life threatening adrenal crisis because their body is no longer capable of producing its own cortisol. The NICE guidelines on glucocorticoid safety highlight the need for doctors to review all concurrent medications when prescribing steroids to prevent these dangerous interactions.
Comparison of Medication-Induced vs. Tumour-Induced Cushing’s
It is important for patients to understand the differences between these two forms of the syndrome, as the diagnostic pathway and the treatment goals are entirely different.
| Feature | Medication-Induced (Exogenous) | Tumour-Induced (Endogenous) |
| Primary Cause | External steroid treatments | Pituitary or adrenal tumours |
| Natural ACTH Level | Very Low | Usually High (unless adrenal tumour) |
| Adrenal Gland Appearance | Often small or shrunken | Enlarged or contains a mass |
| Primary Treatment | Tapering medication doses | Surgical removal of the tumour |
| Prevalence in UK | Very Common | Rare |
In medication induced cases, the goal of the medical team is to find the lowest possible dose of the steroid that still manages the patient’s underlying condition. In tumour based cases, the goal is typically the complete removal of the abnormal tissue to restore natural hormone regulation.
Tapering and Resolving Symptoms
The recovery from medication induced Cushing’s syndrome must be managed slowly and carefully. Because the high levels of medication have caused the natural adrenal glands to go “dormant,” stopping the drug suddenly is extremely dangerous. A gradual reduction, known as tapering, allows the brain and the adrenal glands time to wake up and resume their normal function. This process can take several months or even up to a year, depending on how long the patient was taking the steroids.
As the dose is lowered, the physical symptoms of Cushing’s syndrome, such as the facial swelling and skin changes, usually begin to fade. However, patients may experience “steroid withdrawal” symptoms, including joint pain, fatigue, and low mood, as their body adjusts to lower hormone levels. Throughout this period, UK clinicians monitor patients closely to ensure that the underlying inflammatory condition does not flare up and that the adrenal glands are recovering as expected.
Conclusion
Medications are a frequent cause of Cushing’s syndrome in the UK, often occurring without any underlying adrenal or pituitary tumours. This condition is primarily triggered by the long term use of oral, injected, or highly absorbed topical steroids. While these drugs are essential for managing chronic inflammation, their potential to disrupt the body’s hormonal balance is significant. Recovery requires a slow and medically supervised tapering of the medication to allow the natural adrenal glands to resume their vital functions. If you experience severe, sudden, or worsening symptoms, call 999 immediately.
Can I get Cushing’s from a single steroid injection?
It is extremely rare to develop the syndrome from one injection; it usually requires multiple doses or very high concentrations over time.
Are children more at risk from steroid creams?
Yes, because children have a higher skin surface area relative to their weight, they can absorb more of the medication into their system.
Why did my doctor say my adrenal glands are “sleepy”?
This is a common way to explain adrenal suppression, where external steroids have caused your natural glands to stop producing cortisol.
Can inhaled asthma steroids cause weight gain?
At standard doses, this is unlikely, but at very high doses, enough may be absorbed to cause metabolic changes like weight gain.
Does medication induced Cushing’s go away?
Yes, in most cases, the symptoms resolve once the medication is safely tapered and natural hormone levels return to normal.
Is it safe to stop my steroids if I notice symptoms?
No, you must never stop steroid medication suddenly as it can lead to a life threatening adrenal crisis; always consult your doctor first.
Can antifungal pills make my steroids stronger?
Certain antifungals can slow down the breakdown of steroids in your liver, effectively increasing the dose in your bloodstream.
Authority Snapshot (E-E-A-T Block)
This article is designed to provide clear, medically accurate information regarding the relationship between common medications and the development of Cushing’s syndrome. The content has been written by Dr Rebecca Fernandez and reviewed by Dr Stefan, physicians with extensive experience in the UK healthcare system. All information is grounded in the latest clinical guidelines provided by the NHS and NICE to ensure maximum patient safety.
