Can You Have More Than One Autoimmune Disease?

When someone is diagnosed with an autoimmune disease, they often focus on managing that one condition. However, many people are surprised to learn that it is possible to develop more than one autoimmune disease during their lifetime. In fact, this is more common than many people realise.

Autoimmune diseases occur when the immune system mistakenly attacks the body's own healthy tissues instead of protecting it from infections. There are more than 80 recognised autoimmune conditions, including rheumatoid arthritis, lupus, type 1 diabetes, multiple sclerosis, psoriasis, coeliac disease, and autoimmune thyroid disorders.

What is polyautoimmunity?

Having two or more autoimmune diseases is known as polyautoimmunity. According to a study published in the 'Journal of Research in Medical Sciences', the conditions may develop at the same time or appear years apart. Some people may have two autoimmune diseases, while others may eventually be diagnosed with three or more.

According to Dr Tushar Tayal, Associate Director - Internal Medicine at CK Birla Hospital, Gurugram, this happens far more often than most people realise.

"This phenomenon is known as polyautoimmunity, where a patient develops two or more distinct autoimmune conditions simultaneously or sequentially. In my clinical experience, once someone has one autoimmune diagnosis, their risk of developing another rises considerably compared to the general population," he explains.

Also Read: Can Stress Trigger Autoimmune Diseases? What Science Says

Why does it happen?

Researchers believe that genetics plays a major role. Many autoimmune diseases share similar genes that regulate the immune system. If a person inherits these genes, their immune system may be more likely to become overactive and attack different parts of the body.

Dr Tayal explains that many autoimmune diseases involve overlapping genes related to immune regulation. This means the same genetic tendency that triggers one condition may also increase the risk of developing another.

Apart from genetics, several environmental factors may also contribute. As per a study published in the journal ‘Viruses’, viral infections, smoking, chronic stress, hormonal changes, and certain medications may trigger autoimmune diseases in people who are already genetically susceptible. While these factors do not directly cause autoimmune diseases, they may influence when and how they develop.

Which autoimmune diseases commonly occur together?

Some autoimmune diseases are more likely to occur alongside others. Common combinations include:

• Autoimmune thyroid disease with type 1 diabetes
• Rheumatoid arthritis with Sjögren's syndrome
• Lupus with antiphospholipid syndrome
• Psoriasis with psoriatic arthritis
• Coeliac disease with autoimmune thyroid disease

These combinations occur because the diseases often share similar immune pathways and genetic risk factors.

Also Read: Why Women Are More Likely to Develop Autoimmune Diseases, Study Shows

What symptoms should you watch for?

People who already have one autoimmune disease should pay attention to any new or unusual symptoms. It is easy to assume that every symptom is related to the original diagnosis, but that is not always the case. Warning signs may include:

• Persistent fatigue that worsens over time
• New joint pain or swelling
• Skin rashes
• Unexplained weight changes
• Digestive problems
• Dry eyes or dry mouth
• Numbness or tingling in the hands or feet
• Muscle weakness
• Hair loss or changes in thyroid function

These symptoms do not necessarily mean another autoimmune disease has developed, but they should not be ignored.

Why early diagnosis matters

Diagnosing a second autoimmune disease early can prevent complications and improve long-term health. If symptoms are recognised promptly, doctors can adjust treatment plans before significant damage occurs.

Also Read: Thyroid and Diabetes Connection: What Happens When You Have Both Conditions?

Dr Tayal says that this is why he routinely screens patients with an existing autoimmune disease for signs of another condition rather than assuming new complaints are simply part of the original illness.

This careful approach helps ensure that patients receive the correct diagnosis instead of living with untreated symptoms.

Can more than one autoimmune disease be treated?

Although there is currently no cure for most autoimmune diseases, many can be managed successfully with the right treatment. Medicines that reduce inflammation or regulate the immune system can help control symptoms and prevent further damage.

Treatment plans depend on the specific diseases involved. Some medicines may improve more than one autoimmune condition, while others need to be tailored to each illness. Regular follow-up appointments are important to monitor symptoms and adjust medications if necessary.
Alongside medical treatment, maintaining a healthy lifestyle can support overall well-being. Eating a balanced diet, exercising regularly, getting enough sleep, managing stress, and avoiding smoking can all help reduce inflammation and improve quality of life.

Final Word

Having one autoimmune disease does not guarantee that another will develop, but it does increase the risk. This condition, known as polyautoimmunity, is more common than many people think because many autoimmune diseases share similar genetic and immune system pathways. For people already living with an autoimmune disease, staying alert to new symptoms and attending regular medical check-ups can make a significant difference.