First line investigation in patient with pruritus with no obvious cause: (1)
- detailed history and examination -
- timing of itch - day or night, intermittent or continuous
- nature – burning (in Hodgkin disease), pricking (occurs most frequently after hot baths in polycythaemia rubra vera patients), crawling
- location - scapula/subscapular area, palms of hand and soles of feet (in cholestasis)
- provoking factors - activity/exercise, cold, water, sunlight
- medications – opioids
- physical examination – dry skin, scabies, mental status
- laboratory investigations
- urine - dipstick for glucose
- blood tests - FBC, ESR, U+Es, Ca, LFTs, Fe, TFTs, immunoglobulins
- other investigations
- consider chest X-ray
- abdominal ultrasound (lymphoma)
- skin biopsy
Patients who complain of itch who have a definite skin lesion do not usually need further investigation. Exceptions include the use of patch testing in suspected allergies and a skin biopsy in the case of suspected dermatitis herpetiformis.
Reference:
- Ständer S, Zeidler C, Augustin M, et al. S2k guideline: diagnosis and treatment of chronic pruritus. J Dtsch Dermatol Ges. 2022 Oct;20(10):1387-402.