addison's disease

Addison's disease is a condition in which you do not make enough cortisol and other hormones in your adrenal glands. Various symptoms develop if the cortisol level becomes too low. A very low cortisol level can be life-threatening. Treatment is with replacement hormone tablets which you need to take every day.

What is Addison's disease?

Addison's disease is a condition in which your adrenal glands do not make enough of certain hormones. The condition is named after a Dr Thomas Addison who first described it in 1855. Addison's disease is rare. Just over 8,000 people in the UK have Addison's disease at any one time. Most cases first develop in people aged between 30 and 50, but it can occur at any age.

What are the adrenal glands and what do they do?

You have two small adrenal glands that lie just above each kidney. Each adrenal gland has an outer part (adrenal cortex) and an inner part (adrenal medulla). Cells in the adrenal glands make various hormones. A hormone is a chemical which is made in one part of the body but passes into the bloodstream and has effects on other parts of the body.

Cells in the adrenal cortex (the outer part of the adrenals) make the hormones cortisol and aldosterone. The amount of cortisol that is made is controlled by another hormone called adrenocorticotrophic hormone (ACTH). ACTH is made in the pituitary gland (a small gland that lies just under the brain). ACTH passes into the bloodstream, is carried to the adrenal glands, and stimulates the adrenal glands to make cortisol.

Cortisol is a hormone that is vital for health.

It has many functions which include:

Helping to regulate blood pressure.

Helping to regulate the immune system.

Helping to balance the effect of insulin in regulating the blood sugar level.

Helping the body to respond to stress.


Aldosterone helps to regulate salts in the blood and helps to control blood pressure.

Cells in the adrenal medulla (inner part of the adrenals) make the hormones adrenaline and noradrenaline. These have various actions throughout the body.

If you have autoimmune Addison's disease you have a higher-than-average chance of other autoimmune diseases developing, such as thyroid problems, vitiligo, and pernicious anaemia.


Cortisol replacement - special circumstances

If you have Addison's disease, it is vital that you take the right amount of cortisol replacement (hydrocortisone) every day.


Without this replacement medicine you can become very ill. 


So for example, if you have an illness such as an infection, or an accident, or anything else causing major stress, such as an operation, you need extra hydrocortisone. Your doctor may advise you on some general "sick day rules" to follow. For example, this may include:

  • If you have a fever of 37.5°C or more - double your normal dose. Triple the dose for fever of 39°C or more. Call a doctor if you have a fever of more than 40°C.
  • If you have any serious injury - take 20 mg hydrocortisone immediately (in addition to your normal doses for the day).
  • If you vomit once - take 20 mg hydrocortisone immediately after you vomit. Also, make sure you have plenty to drink to make sure you do not become dehydrated.
  • If you vomit twice or more - use an emergency injection of hydrocortisone (described below) and call a doctor for advice. Make sure that any doctor knows you have Addison's disease and this, in addition to the cause of the illness, needs attention.
  • If you are about to have any operation, dental procedure, or medical procedure such as an endoscopy - you must make sure that the doctor, dentist or anaesthetist knows that you have Addison's disease. You will need extra doses of hydrocortisone.

Basically, for any illness, injury, or operation, you need extra hydrocortisone. This can be taken as tablets but an emergency injection of hydrocortisone might be appropriate as an alternative, especially for situations such as a serious injury. And when you are ill, if you become dizzy or faint, this is a good indication that you might need a drip of fluid. Call a doctor immediately if this occurs and state that you have Addison's disease.