From the Guidelines
A comprehensive pruritus screen should include a full blood count and ferritin levels, as iron deficiency is a common cause of generalized pruritus without rash (GPWOR) 1. When investigating generalized pruritus, it is essential to consider the potential underlying causes, including iron deficiency, which can be easily identified with a full blood count and ferritin levels.
- The British Association of Dermatologists' guidelines recommend checking full blood count and ferritin levels in all patients with chronic GPWOR 1.
- If iron deficiency is suspected, and ferritin is apparently ‘normal’, it may be necessary to check serum iron and total iron binding capacity as well 1.
- A trial of iron replacement should be given if the ferritin is below the lower limit of the reference range or if there is anaemia or microcytosis not attributable to any other cause 1. Additionally, other investigations such as liver function tests (LFTs), renal function tests, and thyroid function tests may be considered based on the patient's clinical presentation and risk factors 1.
- Patients with generalized pruritus with suspicion of haematological involvement should have initial investigations including full blood count, blood film, lactate dehydrogenase, and erythrocyte sedimentation rate 1.
- Testing for hepatitis B and C antibodies, HIV, and other infections should also be considered in patients with risk factors or suggestive symptoms 1.
From the Research
Blood Tests for Pruritis Screen
The following blood tests are recommended as part of a pruritis screen:
- Complete blood count with differential 2, 3, 4
- Liver function tests, including:
- Renal function tests, including:
- Thyroid function tests, including:
- Iron studies 2
- Fasting glucose or A1C level 2
- Erythrocyte sedimentation rate 2
- HIV screening 2
- Hepatitis serologies 2
Additional Tests
Additional tests may be appropriate based on the patient's history and physical examination, such as: