Why does polycythaemia vera cause persistent itching?

Polycythaemia vera is a blood disorder in which the bone marrow makes too many blood cells. Cells and chemical messengers released from the blood can stimulate nerve endings in the skin. Warm baths or showers may intensify this response, so the itch can start or become stronger after washing. It may affect large areas of skin without a visible rash, although scratching can cause redness, soreness, or broken skin.

Persistent itching has many possible causes, including dry skin, allergies, medicines, liver or kidney problems, and other blood conditions. Itching alone cannot identify polycythaemia vera. A clinician may consider it alongside symptoms such as headaches, dizziness, unusual sweating, redness, or clotting concerns and arrange blood tests.

Book a medical review for ongoing or unexplained itching, especially when it follows warm water or occurs with fatigue, headaches, dizziness, or unusual skin redness. Use lukewarm rather than hot water, apply a fragrance-free moisturiser after washing, keep nails short, and choose loose soft clothing. Do not start aspirin or blood-thinning treatment for this symptom without medical advice.

Seek urgent help for sudden weakness, facial drooping, trouble speaking, chest pain, severe breathlessness, one-sided leg swelling, or a sudden severe headache. These may indicate a clot or another emergency and should not be managed as simple itching.

Ask whether a full blood count and other tests are appropriate, whether your medicines could be contributing, and which treatments can reduce the itch safely. Discuss skin-care products and what symptoms would require same-day review.