http://www.fpnotebook.com/
Pruritic Condition
Aka: Pruritic Condition, Pruritus, Itch
- See Also
- Pruritus Causes
- Pruritus Management
- Definition: Pruritus
- Unpleasant cutaneous sensation provoking scratching
- Itch
- Epidemiology
- Very common in elderly patients
- Pathophysiology
- Nerve fiber involvement
- Origin of itch is within skin free nerve endings
- Fibers most concentrated in wrists and ankles
- Unmyelinated C fibers to dorsal horn in spinal cord
- Scratching is a spinal reflex response
- Ascends to cerebral cortex via spinothalamic tract
- Chemical mediators
- Substance P
- Opioid and nonopioid peptides
- Somatostatin
- Neurokinin A
- Histamine
- Serotonin
- Prostaglandins
- External mediators
- Skin inflammation
- Environmental heat or dryness
- Vasodilation
- Psychological concerns
- Causes
- See Pruritus Causes
- Evaluation
- Identify primary Dermatologic Causes of Pruritus
- Atopic Dermatitis: Atopy, Asthma, or Urticaria
- Contagious contacts (Pediculosis or Scabies)
- Consider Localized Causes of Pruritus
- Consider Timing (Xerotic Eczema worse in winter)
- Identify potential exposures
- See Environmental Causes of Pruritus
- See Medication Causes of Pruritus
- Review mental health concerns (e.g. Major Depression)
- Consider Systemic Causes of Pruritus
- Observe for cholestasis (e.g. Jaundice, Hepatomegaly)
- Observe for Lymphadenopathy
- Observe for thyromegaly
- Labs: Systemic Cause Evaluation
- Approach
- Base lab testing on history and physical
- Avoid broad shotgun approach to lab testing
- Dermatologic Cause Evaluation
- Skin Scrapings for Scabies and Dermatophytosis
- Skin biopsy
- Mastocytosis
- Mycosis Fungoides
- Autoimmune Bullous Disease
- Systemic Cause Evaluation
- Thyroid Function Test (evaluate for Hyperthyroidism)
- HIV Test for high risk behaviors
- Liver Function Tests (evaluate for cholestasis)
- Serum Bilirubin
- Alkaline Phosphatase
- Hematologic tests
- Serum Ferritin
- Blood Urea Nitrogen (BUN)
- Complete Blood Count (CBC)
- Calcium
- Albumin
- Radiology: Systemic Cause Evaluation
- Chest XRay (if Lymphoma suspected)
- Right upper quadrant Ultrasound (for cholestasis)
- Complications of persistent scratching
- Bacterial superinfection
- Lichen Simplex Chronicus
- Thickened skin in response to repeated scratching
- Management
- See Nonspecific Management of Pruritus
- References
- Shellow in Goroll (2000) Primary Care, p. 1001-4
- Bernhard (1990) Adv Dermatol 6:57
- Fleisher (1995) Adv Dermatol 10:41
- Garden (1985) Arch Dermatol 121(11):1415-20
- Gilchrest (1982) Arch Dermatol 118(3):154-6
- Greco (1992) J Gen Intern Med 7:340
- Gupta (1992) J Am Acad Dermatol 27(1):118-20
- Hagermark (1995) Semin Dermatol 14:320
- Kam (1996) Anaesthesia 51:1133
- Kantor (1995) Semin Dermatol 14:290
- Millikan (1996) Postgrad Med 99:173
- Swerlick (1985) J Am Acad Dermatol 13(4):675-7
- Teofoli (1996) Int J Dermatol 35:159
- Valsecchi (1983) Arch Dermatol 119(8):630