1. Immune-Related Reactions

Immunotherapy works by stimulating the immune system, which sometimes leads to it attacking healthy tissues, resulting in immune-related side effects. These can affect different organs and may range from mild to severe.

2. Fatigue

Tiredness or fatigue is one of the most common side effects reported by patients undergoing immunotherapy. It can be persistent and may interfere with daily activities, though it is usually manageable with rest and lifestyle adjustments.

3. Skin Reactions

Patients often experience skin-related issues such as:

Rash

Itching

Dryness

Redness or peeling

These typically appear on the face, trunk, or limbs and may signal inflammation caused by an overactive immune response.

4. Gastrointestinal Issues

Some patients develop inflammation in the digestive tract, leading to:

Diarrhoea

Nausea

Abdominal pain

Colitis (inflammation of the colon

5. Lung Inflammation (Pneumonitis)

A rare but serious side effect is pneumonitis, where the lungs become inflamed, causing symptoms such as:

Cough

Shortness of breath

Chest pain

This requires immediate medical attention and may need steroids or hospitalisation.

6. Liver Inflammation (Hepatitis)

Immunotherapy can cause the immune system to attack the liver, leading to elevated liver enzymes and symptoms such as:

Jaundice

Fatigue

Dark urine

Abdominal discomfort

Routine blood tests are often done to monitor liver function.

7. Endocrine System Effects

The immune system may affect glands that regulate hormones, leading to conditions such as:

Thyroid dysfunction (hypothyroidism or hyperthyroidism)

Adrenal insufficiency

Diabetes

Symptoms can include weight changes, mood swings, and energy loss. Hormone replacement therapy may be needed.

8. Infusion Reactions

Some patients experience allergic-like reactions during or shortly after immunotherapy infusions. Symptoms may include:

Fever

Chills

Dizziness

Headache

Low blood pressure

These reactions are usually manageable and occur during the initial treatment cycles.

9. Neurological Effects (Rare)

In rare cases, the immune system may affect the brain or nerves, causing:

Headaches

Confusion

Seizures

Peripheral neuropathy (numbness or tingling in limbs)