Fast Fact and Concept #37: Pruritus

Title: Fast Fact and Concept #37: Pruritus

Author(s): Charles von Gunten; Frank Ferris

Pruritus (itching) is a common and often distressing symptom near the end of life. The itch sensation may arise from stimulation of the skin itch receptor via unmyelinated C fibers, or itch may arise as a central phenomenon without skin involvement (e.g. opioid induced pruritus). Although histamine causes pruritus, many patients with pruritis show no signs of histamine release. Besides histamine, serotonin, prostaglandins, kinins, proteases and physical stimuli have all been implicated as mediators of pruritus.

Management

Management of pruritus involves eliminating the cause when possible. Common causes include: Dermatological (dryness, wetness, irritation, eczema, psoriasis), Metabolic (hepatic failure, renal failure, hypothyroidism), Hem/Onc (iron deficiency, polycythemia, thrombocytosis, leukemia, lymphoma), Drugs (opioids, aspirin, drug reactions), Infection (scabies, lice, candida), Allergy (urticaria, contact dermatitis), and Psychogenic.

Moisturizers

Dryness (xerosis) is very common and may exacerbate other causes. The mainstay of treatment is skin hydration. Note: Most OTC preparations only have small amounts of moisturizer-they are mostly water. Serious dryness requires emollients and moisturizers (such as petroleum jelly) that patients find oily or greasy. Nevertheless, they may applied after bathing, over damp skin, with a superficial covering.

Cooling agents

(e.g. Calamine or Menthol in aqueous cream, 0.5%-2%) are mildly antipruritic. They may act as a counterirritant or anesthetic. A more direct way to anesthetize the skin is with the eutectic mixture of local anesthetics lidocaine and prilocaine (EMLA cream).

Antihistamines

may be helpful in relieving itch when associated with histamine release. Morphine causes non-immune mediated histamine release from mast cells. Although there is little data, many report advantages of combining H1 and H2 receptor subtype antihistamines. These may have central effects as well as peripheral antihistaminic effects. Doxepin, a tricyclic antidepressant, is a very potent antihistamine and may help in more refractory cases, 10-30 mg po qhs.

Topical steroids

may be helpful in the presence of skin inflammation. These may be best applied in ointment rather than cream formulations to alleviate dryness. Systemic steroids have been used in refractory cases.

Other

An old-fashioned but effective remedy is immersion in an oatmeal bath (Aveeno). More recent pharmacological treatments include cholestyramine for cholestatic pruritis, and in other selected patients, ondansetron, paroxetine or naloxone.

Reference:

Alan B. Fleisher, Jr and Jason R. Michaels. Pruritus. In: Principles & Practice of supportive Oncology. Eds: Ann Berger, Russell K. Portenoy, David E. Weissman. Lippincott-Raven Publishers Philadelphia 1998;245-250.

Krajnik M and Zylicz. Understanding pruritis in systemic disease. J Pain Symp Manage 2001;21:151-168.

Wilde MI, Markham A. Ondansetron: a review of its pharmacology and preliminary clinical findings in novel applications. Drugs 1996;52:773-794.

Zylicz Z, Smits C, Chem D and Krajnik M. Paroxetive for pruritis in advanced cancer. J Pain Symptom Manage 1998;16:121-124.

Copyright Notice: Users are free to download and distribute Fast Facts for educational purposes only. Citation for referencing: von Gunten CF, Ferris F, and Weissman DE. Fast Facts and Concepts #37: PRURITUS; March, 2001. End-of-Life Physician Education Resource Center www.eperc.mcw.edu.

Fast Facts and Concepts was originally developed as an end-of-life teaching tool by Eric Warm, MD, U. Cincinnati, Department of Medicine. See: Warm, E. Improving EOL care--internal medicine curriculum project. J Pall Med 1999; 2: 339- 340.

Contact: David E. Weissman, MD, FACP Editor, Journal of Palliative Medicine Palliative Care Program Director Medical College of Wisconsin (P) 414-805-4607 (F) 414-805-4608

Disclaimer: Fast Facts provide educational information, this information is not medical advice. Health care providers should exercise their own independent clinical judgment. Some Fast Fact information cites the use of a product in dosage, for an indication, or in a manner other than that recommended in the product labeling. Accordingly, the official prescribing information should be consulted before any such product is used.

Creation Date: 3/2001

Format: Handouts

Purpose: Instructional Aid, Self-Study Guide, Teaching

Audience(s)

Training: Fellows, 3rd/4th Year Medical Students, PGY1 (Interns), PGY2-6, Physicians in Practice

Specialty: Anesthesiology, Emergency Medicine, Family Medicine, General Internal Medicine, Geriatrics, Hematology/Oncology, Neurology, OB/GYN, Ophthalmology, Pulmonary/Critical Care, Pediatrics, Psychiatry, Surgery

Non-Physician: Nurses

ACGME Competencies: Medical Knowledge, Patient Care

Keyword(s): Skin, lymphatic

The Fast Facts series is distributed for educational use only and does not constitute medical advice. For the most current version of Fast Facts visit the EPERC web site at www.eperc.mcw.edu. This mirror version is provided subject to copyright restrictions for educational use within the Inter-Instutional Collaborating Network on End-of-Life Care (IICN).