Immunotherapy has fundamentally changed the landscape of melanoma treatment by utilising the body’s own immune system to identify and destroy cancer cells. While this approach is often highly effective, the activation of the immune system can sometimes lead to inflammation in healthy tissues and organs. These reactions, known as immune-related adverse events, range from mild skin irritations to more significant organ-based complications that require careful medical management and monitoring.
What We’ll Discuss in This Article
- The most common side effects affecting the skin and digestive system.
- How immunotherapy can impact hormone-producing glands in the body.
- Serious but less common inflammatory reactions in the lungs and liver.
- The timeline for when side effects typically appear during treatment.
- How healthcare teams manage immune-related reactions using steroids.
- The importance of regular blood tests and clinical monitoring.
- When to seek urgent medical attention for specific symptoms.
Common skin-related reactions to immunotherapy
Skin problems are among the most frequently reported side effects for individuals receiving immunotherapy for melanoma in the UK. Many patients experience a red, patchy rash or areas of the skin that become notably dry and itchy. In some cases, people may notice a loss of skin pigment in certain areas, a condition known as vitiligo, which occurs because the immune system is targeting the pigment-producing cells. Most skin reactions are mild and can be managed effectively with moisturising creams or topical steroid ointments provided by your clinical team. It is important to report any new rash or skin changes immediately, especially if the skin begins to blister or peel, as this can indicate a more serious inflammatory response.
Gastrointestinal side effects and bowel inflammation
Immunotherapy can often cause changes in bowel habits, which may range from mild loose stools to more significant diarrhoea. A more serious condition known as colitis occurs when the lining of the large bowel becomes inflamed due to the heightened immune response. Symptoms of colitis include frequent watery or soft stools, abdominal pain, cramping, and occasionally the presence of blood or mucus in the poo. If these symptoms develop, it is essential to inform your oncology team before taking any over-the-counter anti-diarrhoea medication. Managing bowel inflammation early is vital to prevent dehydration and further complications within the digestive tract.
The impact on hormone-producing endocrine glands
The endocrine system, which includes glands like the thyroid, pituitary, and adrenal glands, can also be affected by immunotherapy. Inflammation in these glands can cause them to produce too much or too little of specific hormones, leading to a variety of symptoms. For example, an underactive thyroid (hypothyroidism) might make you feel extremely tired, cold, or prone to weight gain. Conversely, inflammation of the pituitary gland, known as hypophysitis, can cause persistent headaches, changes in vision, and extreme fatigue. Regular blood tests are performed before every treatment session to monitor hormone levels and ensure that any endocrine changes are identified and treated with hormone replacement therapy.
Identifying inflammation in the lungs and liver
While less common, immunotherapy can cause inflammation in the lungs, a condition called pneumonitis, or in the liver, known as hepatitis. Pneumonitis may present as a new or worsening cough, shortness of breath, or chest pain, even when at rest. Hepatitis often occurs without obvious symptoms and is usually first detected through routine blood tests showing elevated liver enzymes. However, some people may notice yellowing of the skin or eyes, dark urine, or pain on the right side of the abdomen. Early identification of these organ-based inflammatory reactions allows the medical team to pause treatment and start the appropriate medications to reduce the inflammation.
General symptoms and infusion-related reactions
Many people feel a general sense of fatigue or flu-like symptoms during their course of immunotherapy. This can include feeling very tired, having a mild fever, chills, or muscle and joint aches. These symptoms often reflect the immune system being in an active state. Additionally, some patients may experience an infusion-related reaction while the drug is being administered. This might cause a sudden rash, shortness of breath, or a drop in blood pressure during the drip. Clinical staff monitor patients closely during every infusion to ensure that any immediate reactions are treated promptly with anti-allergy medications.
Managing side effects with steroid medications
The primary way that doctors manage significant immune-related side effects is through the use of corticosteroids, such as prednisolone. Steroids work by dampening down the overactive immune response and reducing the inflammation in the affected organs. Depending on the severity of the reaction, your oncologist may need to pause your immunotherapy for a few weeks while you take a course of steroids. For most people, the side effects resolve once the inflammation is controlled, allowing them to potentially restart their treatment. It is essential to follow the specific instructions for tapering steroid doses, as stopping them too quickly can cause the side effects to return.
The importance of the 24-hour contact number
Because the side effects of immunotherapy can become serious very quickly, every patient in the UK is provided with a 24-hour emergency contact number for their oncology unit. You are encouraged to call this number at any time of the day or night if you feel unwell or notice any new symptoms. Early communication is the most effective way to manage the risks associated with these drugs. You will also be given an immunotherapy alert card to carry in your wallet. This card informs other healthcare professionals, such as paramedics or doctors in an emergency department, that your symptoms may be caused by your cancer treatment and require specific management.
Long-term and delayed side effects
Most immune-related side effects occur within the first few months of starting treatment, but it is important to know that they can appear at any time. Some people may even develop side effects several months or even a year after their last dose of immunotherapy has been completed. This is because the immune system can remain in an active state for a long time. Ongoing vigilance and regular follow-up appointments are necessary even after the active phase of treatment has finished. Being aware of potential late effects ensures that you can continue to manage your health effectively in the long term.
Conclusion
Immunotherapy for melanoma can cause a wide range of side effects due to the activation of the immune system against healthy tissues. While common issues include skin rashes and fatigue, more serious inflammation can occur in the bowels, lungs, liver, or hormone glands. Most of these reactions are manageable through early reporting and the use of steroid medications to control the inflammation. If you experience severe, sudden, or worsening symptoms, call 999 immediately.
How soon do immunotherapy side effects usually start?
Many side effects appear within a few weeks of the first dose, but they can occur at any point during treatment or even months after it has finished.
Will I lose my hair with immunotherapy?
Hair loss is very rare with immunotherapy, although some people may notice a slight thinning of their hair or changes in skin and hair pigment.
What should I do if I get diarrhoea during treatment?
You should contact your oncology team on the 24-hour number immediately and avoid taking over-the-counter anti-diarrhoea medicines unless instructed by them.
Can side effects mean the treatment is working?
While some studies suggest a link between certain side effects and treatment response, many people have excellent results with very few or no side effects at all.
Are the side effects of combination therapy worse?
Yes, using two immunotherapy drugs together, such as nivolumab and ipilimumab, is generally associated with a higher risk of more frequent and severe side effects.
Can side effects of immunotherapy be permanent?
Most side effects are temporary, but some hormonal changes, such as an underactive thyroid or diabetes, may require long-term medication.
What is the role of steroids in my treatment?
Steroids are used as a rescue medication to reduce inflammation if the immunotherapy starts to affect your healthy organs or tissues.
Authority Snapshot (E-E-A-T)
This article is designed to provide clear and factual information regarding skin health for the general public. The content is written by the Medical Content Team and has been reviewed by Dr. Stefan Petrov. He is a UK-trained physician with an MBBS and postgraduate certifications including Basic Life Support (BLS), Advanced Cardiac Life Support (ACLS), and the UK Medical Licensing Assessment (PLAB 1 & 2). He has hands-on experience in general medicine, surgery, anaesthesia, ophthalmology, and emergency care. Dr. Petrov has worked in both hospital wards and intensive care units, performing diagnostic and therapeutic procedures, and has contributed to medical education by creating patient-focused health content and teaching clinical skills to junior doctors.
