Pruritus - Chronic Itch

Pruritus is the medical term for itch. Pruritus is often described by patients as more disabling than pain causing a detrimental effect on one’s entire life including sleep, concentration, mood and relationships.

What are the causes of itch?

Pruritus can be thought of as a skin disease (or rash) that itches or an itch that over time rashes. This simply analogy used by Dr Nelson helps patients explore if the problem lies with the skin itself e.g. a primary skin disease such as eczema or it is a sensation of itch brought on by an underlying medical ailment.

Skin diseases that are typically very itchy include

• Eczema
• Urticaria
• Scabies
• Dermatitis herpetiformis
• Lichen simplex
• Bullous pemphigoid

Underlying medical causes of itch include:

• Medication side effect
• Renal failure
• Liver disease
• Haematological disease including anaemia, lymphoma
• Thyroid disease

Treatment of itch

Pruritus can be localised or generalised. This feature is important when considering treatment.

Localised itch can usually be treated with a cream or ointment directly onto the area. Widespread pruritus is hard to treat with a topical remedy therefore, a medication may be preferable. Light therapy (phototherapy) is a very effective and safe form of treatment for generalised pruritus.

How do you investigate the cause of pruritus?

In order to establish the cause of pruritus a full medical history is taken including all medication and when the medication was started in relation to the start of the problem. The skin should be examined for signs of primary skin disease. A further medical examination should be performed looking for signs of underlying causes. Investigations that are often considered in blood tests looking at the full blood count, kidney and liver function, iron levels, thyroid function. Other tests looking for specific causes maybe consider depending on the clinical situation. Treatment can often be started while awaiting the results of investigations.

Is there anything I can do to help with my itch?

Antihistamines can be tried for pruritus brought on by urticaria but they are rarely of help in other causes. A bland moisturiser is usually very helpful in dry skin conditions combined with a topical corticosteroid.  Try not to scratch as the more the area is scratched typically the worse it gets. If you find you have entered into an intractable itchy scratch rub cycle you should seek medical input.