Addison's disease

Addison’s disease (also known as primary adrenal insufficiency or hypoadrenalism) is a rare disorder of the adrenal glands.

The adrenal glands are two small glands that sit on top of the kidneys. They produce two essential hormones: cortisol and aldosterone.

In Addison's disease, the adrenal gland is damaged, and not enough cortisol and aldosterone are produced.

About 8,400 people in the UK have Addison's disease. It can affect people of any age, although it's most common between the ages of 30 and 50. It's also more common in women than men.

Early-stage symptoms of Addison’s disease are similar to other more common health conditions, such as depression or flu. You may experience:

• fatigue (lack of energy or motivation)
• muscle weakness
• low mood
• loss of appetite and unintentional weight loss
• increased thirst

Over time, these problems may become more severe and you may experience further symptoms, such as dizziness, fainting, cramps and exhaustion. You may also develop small areas of darkened skin, or darkened lips or gums.

Although these symptoms aren’t always caused by Addison’s disease, you should see your GP, so they can be investigated.

Read more about the symptoms of Addison’s disease and diagnosing Addison’s disease.

Why it happens

The condition is usually the result of a problem with the immune system, which causes it to attack the outer layer of the adrenal gland (the adrenal cortex), disrupting the production of steroid hormones aldosterone and cortisol. It's not clear why this happens, but it's responsible for 70-90% of cases in the UK.

Other potential causes include conditions that can damage the adrenal glands, such as tuberculosis (TB), although this is uncommon in the UK.

Read more about the causes of Addison’s disease.

Information about you

If you have Addison's disease, your clinical team will pass information about you on to the National Congenital Anomaly and Rare Diseases Registration Service (NCARDRS).

This helps scientists look for better ways to prevent and treat this condition. You can opt out of the register at any time.

Find out more about the register.

Symptoms

Addison's disease can be difficult to detect at first, because early symptoms are similar to symptoms of many other health conditions.

Initial symptoms of Addison's disease can include:

• fatigue (lack of energy or motivation)
• lethargy (abnormal drowsiness or tiredness)
• muscle weakness
• low mood (mild depression) or irritability
• loss of appetite and unintentional weight loss
• the need to urinate frequently
• increased thirst
• craving for salty foods

Dehydration can also be an early sign of Addison’s disease. It's caused by lack of the hormone aldosterone in your body, which is used to regulate the balance of salt and water.

Later symptoms

Further symptoms of Addison’s disease tend to develop gradually over months or years. However, additional stress, caused by another illness or an accident, for example, may cause your symptoms to suddenly get worse.

You may go on to develop:

• low blood pressure when you stand up, which can cause dizziness and fainting 
• feeling sick (nausea)
• vomiting
• diarrhoea
• abdominal, joint or back pain
• muscle cramps 
• chronic exhaustion, which may cause depression
• brownish discolouration of the skin, lips and gums (hyperpigmentation), particularly in the creases on your palms, on scars or on pressure points, such as your knuckles or knees
• a reduced libido (lack of interest in sex), particularly in women

Some women may also have irregular periods or miss some periods completely. Children with Addison's disease may experience puberty later than usual.

Some people with Addison's disease also develop low blood sugar (hypoglycaemia). This can cause symptoms such as difficulty concentrating, confusion, anxiety and even unconsciousness (particularly in children).

If you're experiencing symptoms of Addison's disease, see your GP so they can diagnose or rule out the condition. These symptoms will usually improve with appropriate treatment.

Read more about diagnosing Addison's disease and treating Addison's disease.

Adrenal crisis

If Addison’s disease is left untreated, the levels of hormones produced by the adrenal gland gradually decrease in the body. This causes your symptoms to get progressively worse and eventually lead to a life-threatening situation called an adrenal or Addisonian crisis.

During an adrenal crisis, the symptoms of Addison’s disease appear quickly and severely. This could happen when you're already experiencing initial symptoms or without any symptoms at all.

Signs of an adrenal crisis include:

• severe dehydration
• pale, cold, clammy skin
• sweating
• rapid, shallow breathing
• dizziness
• severe vomiting and diarrhoea
• severe muscle weakness
• headache
• severe drowsiness or loss of consciousness

An adrenal crisis is a medical emergency. If left untreated, it can be fatal. If you think you or someone you know with Addison’s disease is having an adrenal crisis, dial 999 for an ambulance.

If an adrenal crisis isn't treated, it can lead to a coma and death. There's also a risk your brain won't get enough oxygen if treatment is delayed, which can cause permanent disability.

Causes

Addison's disease develops when the outer layer of your adrenal glands (your adrenal cortex) is damaged, reducing the levels of hormones it produces.

Problems with the immune system

In the UK, a problem with the immune system is the most common cause of Addison's disease, accounting for 70-90% of cases.

The immune system is your body’s defence against infection and disease. If you're ill, your immune system produces antibodies (a special type of protein that destroys disease-carrying organisms and toxins). These antibodies attack the cause of the illness.

However, if you develop a problem with your immune system, it can start to attack your own healthy tissues and organs. This is known as an autoimmune disorder.

Addison’s disease can develop if your immune system attacks your adrenal glands and severely damages your adrenal cortex. When 90% of the adrenal cortex is destroyed, your adrenal glands won't be able to produce enough of the steroid hormones cortisol and aldosterone. Once levels of these start decreasing, you'll experience symptoms of Addison’s disease.

It's not clear why some people develop this problem with their immune system, although it can run in families (see below).

Genetics

Research has shown that some people with certain genes are more likely to develop autoimmune disorders.

It's not clear how these genes lead to Addison's disease and similar conditions, but it does mean your risk of developing Addison's disease is increased if you or a close family member have another autoimmune condition, such as:

• vitiligo – a chronic (long-term) condition that causes pale, white patches to develop on the skin
• type 1 diabetes – a chronic condition caused by too much glucose in the blood  
• underactive thyroid gland (hypothyroidism) 

Other causes

Tuberculosis (TB) is the most common cause of Addison's disease worldwide, but is rare in the UK. TB is a bacterial infection that mostly affects the lungs, but can also spread to other parts of your body. It can cause Addison’s disease if it damages your adrenal glands.

Other possible causes of Addison’s disease include:

• infections – such as those linked to AIDS, or fungal infections
• a haemorrhage – very heavy bleeding into the adrenal glands, sometimes associated with meningitis or other types of severe sepsis
• cancer – if cancer cells from elsewhere in your body spread to your adrenal glands
• amyloidosis – a disease where amyloid, a protein produced by your bone marrow cells, builds up in your adrenal glands and damages them
• surgical removal of both adrenal glands (adrenalectomy) – for example, to remove a tumour
• adrenoleukodystrophy (ALD) – a rare, life-limiting, inherited condition affecting the adrenal glands and nerve cells in the brain that most often affects young boys
• certain treatments needed for Cushing's syndrome – a collection of symptoms caused by very high levels of cortisol in the body

Diagnosing

Treatment

If you have Addison’s disease, you'll need to take daily medication to replace the lost hormones. This should help you to live an active life, although many people find they still need to manage their fatigue.

In some cases, the underlying causes of Addison’s disease can be treated. For example, tuberculosis (TB) is treated with a course of antibiotics over a period of at least six months.

However, most cases are caused by a problem with the immune system that can't be cured.

Medication for Addison’s disease

Treatment usually involves corticosteroid (steroid) replacement therapy for life. Corticosteroid medication is used to replace the hormones cortisol and aldosterone that your body no longer produces. It's usually taken in tablet form two or three times a day.

In most cases, a medication called hydrocortisone is used to replace the cortisol. Other possible medicines are prednisolone or dexamethasone, though these are less commonly used. 

Aldosterone is replaced with a medication called fludrocortisone. Your GP may also ask you to add extra salt to your daily diet, although if you're taking enough fludrocortisone medicine this may not be necessary. Unlike most people, if you feel the urge to eat something salty, then you should eat it.

In general, the medications used for Addison's disease don't have side effects, unless your dose is too high. If you take a higher dose than necessary for a long time, there's a risk of problems such as weakened bones (osteoporosis), mood swings and difficulty sleeping (insomnia).

Living with Addison’s disease

Many people with Addison’s disease find that taking their medication enables them to continue with their normal diet and exercise routines. However, bouts of fatigue are also common, and it can take some time to learn how to manage these periods of low energy.

Some people find that needing to take regular doses of medication is restrictive and affects their daily life or emotional health. Missing a dose of medication, or taking it late, can also lead to exhaustion or insomnia.

Some people can develop associated health conditions, such as diabetes or an underactive thyroid, which require extra treatment and management.

You'll usually need to have appointments with an endocrinologist every 6-12 months, so they can review your progress and adjust your medication dose, if necessary. Your GP can provide support and repeat prescriptions in between these visits.

Failing to take your medication could lead to a serious condition called an adrenal crisis, so you must:

• remember to collect your repeat prescriptions
• keep spare medication as necessary – for example, in the car or at work, and always carry some spare medication with you
• take your medication every day at the right time
• pack extra medication if you are going away – usually double what you would normally need, plus your injection kit (see below)
• carry your medication in your hand luggage if you are travelling by plane, with a note from your doctor explaining why it is necessary

You could also inform close friends or colleagues of your condition. Tell them about the signs of adrenal crisis and what they should do if you experience one.

Medical alert bracelets

It's also a good idea to wear a medical alert bracelet or necklace that informs people you have Addison’s disease.

After a serious accident, such as a car crash, a healthy person produces more cortisol. This helps you cope with the stressful situation and additional strain on your body that results from serious injury. As your body cannot produce cortisol, you'll need a hydrocortisone injection to replace it and prevent an adrenal crisis.

Wearing a medical alert bracelet will inform any medical staff treating you about your condition, and what medication you require.

Medical alert bracelets or necklaces are pieces of jewellery engraved with your medical condition and an emergency contact number. They are available from a number of retailers. Ask your GP if there's one they recommend, or go to the MedicAlert website. 

If you need to stay in hospital, the healthcare professionals responsible for your care will also need to know you need steroid replacement medication throughout your stay. It's important to note that this advice still applies if you're not supposed to eat or drink (nil by mouth) for any reason.

Adjusting your medication

At certain times, your medication may need to be adjusted to take into account any additional strain on your body. For example, you may need to increase the dosage of your medication if you experience any of the following:

• an illness or infection – particularly if you have a high temperature of 38C (100.4F) or above
• an accident, such as a car crash
• an operation, dental or medical procedure (such as a tooth filling or endoscopy)
• you're taking part in strenuous exercise not usually part of your daily life

This will help your body cope with the additional stress. Your endocrinologist will monitor your dosage and advise about any changes. Over time, as you get used to the condition and learn what can trigger your symptoms, you may learn how to adjust your medication yourself. However, always consult your GP or specialist if you're unsure.

Emergency treatment

You and a partner or family member may be trained to administer an injection of hydrocortisone in an emergency.

This could be necessary if you go into shock after an injury, or if you experience vomiting or diarrhoea and are unable to keep down oral medication. This may occur if you're pregnant and have morning sickness. Your endocrinologist will discuss with you when an injection might be necessary.

If you need to administer emergency hydrocortisone, always call your GP immediately afterwards. Check what out-of-hours services are available in your local area, in case the emergency is outside normal working hours.

You can also register yourself with your local ambulance service, so they have a record of your requirement for a steroid injection or tablets, if you need their assistance.

Treating adrenal crisis

Adrenal crisis, or Addisonian crisis, needs urgent medical attention. Dial 999 for an ambulance if you or someone you know are experiencing adrenal crisis.

Signs of an adrenal crisis include:

• severe dehydration
• pale, cold, clammy skin
• sweating
• rapid, shallow breathing
• dizziness
• severe vomiting and diarrhoea
• severe muscle weakness
• headache
• severe drowsiness or loss of consciousness

In hospital, you'll be given lots of fluid through a vein in your arm to rehydrate you. This will contain a mixture of salts and sugars (sodium, glucose and dextrose) to replace those that your body is lacking. You'll also be injected with hydrocortisone to replace the missing cortisol hormone.

Any underlying causes of the adrenal crisis, such as an infection, will also be treated.