Jul242026
Small, round, pink tablets spill onto a blue surface, spelling out ‘B12’.

What is Pernicious Anaemia?

Quick facts: Pernicious anaemia is an autoimmune condition that affects the body’s ability to absorb enough vitamin B12 from food. Symptoms are similar to other forms of anaemia, including dizziness, weakness and fatigue, while treatments differ in that they focus on supplementing B12 levels rather than iron. Never self-diagnose with pernicious anaemia, as the signs can be confused with other conditions, and over-supplementation can be dangerous.

For most people, the word ‘anaemia’ is all but synonymous with low iron levels – but that’s not always accurate. In fact, anaemia refers to conditions that involve a lack of healthy red blood cells and haemoglobin, and low iron isn’t the only possible cause.

Pernicious anaemia is a rare type of anaemia associated with a vitamin B12 deficiency rather than an iron deficiency.1 It has different causes and requires different treatments compared to the types of anaemia most people are familiar with.

What Causes Pernicious Anaemia?

Pernicious anaemia is an autoimmune condition. It happens when the immune system mistakenly attacks healthy cells in the stomach that produce something called intrinsic factor, which is a protein vital for the absorption of vitamin B12.1

Normally, vitamin B12 from food binds to intrinsic factor in the stomach before being absorbed in the small intestine. When intrinsic factor levels are low, your body will struggle to absorb enough vitamin B12 regardless of how much you consume.3

How does this link to anaemia? Well, amongst other functions, vitamin B12 plays a vital role in the production of healthy red blood cells. Without enough of it, haemoglobin production drops, which can eventually lead to anaemia and a range of associated symptoms.2

The term ‘pernicious anaemia’ refers specifically to the autoimmune condition that causes a lack of intrinsic factor. But it’s also possible to have similar symptoms without the autoimmune condition if you have a B12 deficiency. Fortunately, most people can get enough B12 with ease through a healthy, balanced diet.

What Are the Signs and Symptoms of Pernicious Anaemia?

The symptoms of pernicious anaemia can develop gradually and may vary between individuals. Common signs and symptoms may include:2,3

  • Persistent tiredness and fatigue
  • Weakness
  • Shortness of breath
  • Pale or yellowish skin
  • Dizziness
  • Headaches
  • Heart palpitations
  • Difficulty concentrating
  • Memory problems
  • Tingling or numbness in the hands and feet
  • Balance difficulties
  • Mood changes.

Many of these symptoms can also occur in other health conditions. For this reason, anyone experiencing ongoing symptoms should seek medical advice rather than attempting to self-diagnose.

Healthcare professionals can perform blood tests and other investigations to determine the underlying cause and recommend appropriate treatment.

How to Treat Pernicious Anaemia

Treatment for pernicious anaemia focuses on restoring and maintaining healthy vitamin B12 levels.3 The most suitable treatment plan can depend on factors including how severe your symptoms are, how low your B12 levels are and the details of your personal medical history.

Because the condition affects the body’s ability to absorb vitamin B12 from food, treatment often involves vitamin B12 injections or high-strength oral B12 supplements prescribed and monitored by a healthcare professional. This is to reduce the risk of over-supplementation. 

While vitamin B12 supplements are an important part of treatment for diagnosed pernicious anaemia, it’s vital to avoid self-medicating. This is because:

  • The symptoms of pernicious anaemia are similar to other conditions, meaning you need a medical professional’s help to be sure of your diagnosis
  • If your symptoms are caused by something else, vitamin B12 may not help and might even make things worse
  • Even if you do have a B12 deficiency, taking supplements without medical advice has its risks and can lead to unwanted side effects.

Instead, you should consult your doctor for advice about your symptoms and medical history.

Conclusion

Pernicious anaemia is an autoimmune condition that affects the body’s ability to absorb vitamin B12. Over time, this can lead to vitamin B12 deficiency and anaemia, causing symptoms such as fatigue, weakness and neurological changes. 

Early diagnosis and appropriate medical treatment can help you to manage the condition effectively and support long-term wellbeing.

FAQs

How Rare Is Pernicious Anaemia?

Pernicious anaemia is considered relatively uncommon, although it’s believed to be more common in older populations.. 

Research suggests it affects approximately 0.1% of the general population and around 1–2% of older adults in some populations.4 The condition is more frequently diagnosed in people over the age of 60 and may occur alongside other autoimmune conditions. 

While it’s not one of the most common forms of anaemia, pernicious anaemia remains an important condition because untreated vitamin B12 deficiency can lead to significant health complications.

Can Pernicious Anaemia Be Cured?

Pernicious anaemia is generally considered a lifelong condition because the underlying autoimmune process typically can’t be reversed. However, it can usually be managed effectively with appropriate vitamin B12 treatment prescribed by a healthcare professional.3 

Regular monitoring and ongoing treatment can help you to maintain healthy vitamin B12 levels and reduce the risk of complications.

Why Is It Called ‘Pernicious’ Anaemia?

The term ‘pernicious’ dates back to a time when effective treatment wasn’t available. Before the discovery of vitamin B12 therapy, the condition was often progressive and could lead to serious complications or death – hence the name, referring to something having a very harmful or deadly effect.4 

Today, the outlook for people with pernicious anaemia is much improved thanks to advances in diagnosis and treatment. Many people continue to live normal lives with prescribed vitamin B12 supplementation.

References

(1) NHS. (2024). Vitamin B12 or folate deficiency anaemia – Causes. Retrieved from: https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/causes/

(2) NHS. (2024). Vitamin B12 or folate deficiency anaemia – Symptoms. Retrieved from: https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/symptoms/

(3) NHS. (2024). Vitamin B12 or folate deficiency anaemia – Treatment. Retrieved from: https://www.nhs.uk/conditions/vitamin-b12-or-folate-deficiency-anaemia/treatment/

(4) National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). (2023). Symptoms & Causes of Pernicious Anemia. Retrieved from: https://www.niddk.nih.gov/health-information/blood-diseases/pernicious-anemia/symptoms-causes

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