Private itching all over clinic in London, same-day GP.

Internal causes

• Liver disease — particularly conditions blocking bile flow. Often worst on the hands and feet and at night.
• Chronic kidney disease — common in advanced disease, and often generalised.
• Iron deficiency — a recognised and readily treatable cause, even without anaemia.
• Thyroid disease — both over- and underactive.
• Blood disorders — polycythaemia, and lymphoma. Lymphoma-related itch can precede any other sign by months.
• Diabetes, and rarely internal cancers.
• HIV, and parasitic infection in relevant travel history.

Other common causes

• Dry skin — by far the commonest cause overall, particularly in older people and in winter.
• Medicines — opioids, some antibiotics, ACE inhibitors, statins, and many others. Onset can be weeks after starting.
• Scabies — itching far worse at night, often with other household members affected. The burrows can be subtle.
• Menopause, and pregnancy.
• Anxiety and stress, which amplify itch considerably.
• Neuropathic itch — localised, from nerve compression, often on the back or arms.

What gets tested

• Full blood count and blood film
• Ferritin and iron studies
• Liver function, including bile acids if pregnant
• Kidney function
• Thyroid function, HbA1c
• Inflammatory markers and LDH
• Chest X-ray and further tests where lymphoma is being considered
• HIV testing where relevant

What helps while the cause is found

Standard non-sedating antihistamines help little in itching without a rash, because histamine is usually not the mediator. That is worth knowing before working through several packets.