Systemic conditions play a significant role in the etiology of generalized pruritus, often indicating underlying diseases such as hepatic, renal, haematological, endocrine disorders, or malignancies. In primary care, a thorough assessment is essential to identify these systemic causes early and guide appropriate management.
Assessment should begin with a detailed history and physical examination focusing on the duration, distribution, and characteristics of the itch, as well as associated systemic symptoms like weight loss, night sweats, or jaundice. This helps to differentiate pruritus due to dermatological causes from systemic origins NICE CG57.
Initial investigations in primary care should include basic blood tests such as full blood count, liver and renal function tests, thyroid function tests, and inflammatory markers. These tests help detect common systemic causes like cholestasis, chronic kidney disease, thyroid disorders, or haematological abnormalities NICE CG57.
Referral for further specialist evaluation is warranted if initial tests are inconclusive but clinical suspicion remains high, especially to exclude malignancy or rare systemic diseases. This aligns with NICE guidance on suspected cancer referral pathways when systemic symptoms or abnormal test results are present NICE CG57.
Recent literature emphasizes that chronic pruritus of unknown origin may persist despite negative initial investigations, highlighting the need for ongoing assessment and multidisciplinary management. Interventions may include symptomatic treatment and consideration of less common systemic causes Andrade et al. 2020.
In children and adolescents, systemic causes are less common but should still be considered, particularly in persistent or severe cases, with a similar approach to assessment and referral Kang et al. 2021.