pruritus (itching)
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Introduction
Itching or pruritus is the unpleasant sensation associated with the urge to scratch.
Classification
- pruritoceptive pruritus (primary skin disorder)
- neurogenic pruritus (generalized itching without primary skin disorder)
- neuropathic pruritus (localized itching without primary skin disorder)
- psychogenic pruritus
Etiology
dermatologic causes (pruritoceptive)
- xerosis (dry skin), xerotic eczema, psoriasis, urticaria
- infections, infestations
- physical causes
- sunburn
- fiberglass
- chemical irritants
- too-frequent bathing
- pressure
- low-intensity electrical stimulation
systemic causes (neurogenic)
- uremia, chronic renal failure
- obstructive biliary disease
- hematologic
- endocrine
- pregnancy-related causes
- non-specific pruritus of pregnancy
- intrahepatic cholestasis of pregnancy
- pruritic urticarial papules & plaques of pregnancy (PUPPP)
- malignancy
- systemic medications
- allergy to drug
- idiosyncratic drug reaction
- pruritus-producing drugs
- common, > 15%
- opiates
- statins
- BRAF inhibitors (vemurafenib)
- CTLA-4 inhibitors (ipilimumab)
- EGFR inhibitors (cetuximab)
- hydroxyethyl starch (> 15%)
- others
- oral contraceptives
- barbiturates
- aspirin
- niacin
- phenothiazines
- tolbutamide
- quinidine
- diuretics (includin HCTZ) can worsen xerosis, pruritus
- NSAIDS
- calcium channel blockers
- common, > 15%
- immunostimulation
- immunotherapy during treatment or 21-60 days after treatment
- immunizations: Tdap, mRNA COVID-19 vaccine (within 1 week)[25]
neurologic (neuropathic)
- multiple sclerosis
- stroke
- brain tumor
- brain abscess
- postherpetic neuralgia
- brachioradial pruritus
- trigeminal trophic syndrome
- notalgia paresthetica
- peripheral neuropathy
- 20% of pruritus of unknown etiology with systemic cause[9]
psychological cause (psychogenic)
- psychogenic itching
- neurodermatitis
- stress
- depression
- negative emotions may increase itching & pain[4]
Pathology
- B-type natriuretic peptide is a neurotransmitter for TRPV1-positive itch-specific neurons dorsal root ganglion cells
- gastrin-releasing peptide-connected secondary & tertiary itch receptors in the spinal cord transmit the itch signal to the brain[5]
- activation of mast cells & CD3+ T-cells to overproduce IL-31 (pruritic)
- impaired release prostaglandin D2 (pruritus inhibitor)
Clinical manifestations
- presence of a rash
- preceeding or coincident with pruritus (scratching)
- skin manifestations may not be seen[2]
- scratching can damage skin (excoriation, lichenification)
- pruritus exacerbated by bathing or exposure to water (aquagenic pruritus) suggests polycythemia vera[6]
- medication-induced pruritus may occur after months or years on a drug[2]
* images[18]
Laboratory
pruritus without a rash
- complete blood count (CBC) with differential
- IgE in serum
- thyroid function tests
- serum iron, TIBC, serum ferritin
- liver function tests
- renal function tests
- serum glucose, hgbA1c[24]
- cytokines (if severe & refractory)
- consider age & gender-appropriate cancer screening as indicated by clinical presentation
Radiology
Complications
- risk factor for hematologic malignancy & bile duct cancer but not other malignancies[11]
Management
- general measures
- topical agents
- emollients (moisturizing agents)
- camphor/menthol/phenol soothe by counter irritation
- topical anesthetics[2]
- topical glucocorticoids
- topical calcineurin inhibitors
- topical tacrolimus, topical picrolimus[2]
- systemic agents
- systemic glucocorticoids for severe, intractable itching
- glucocorticoids may not improve neurogenic pruritus or psychogenic pruritus[2]
- antihistamines
- hydroxyzine (Atarax)
- chlorpheniramine
- diphenhydramine (Benadryl)
- non-sedating antihistamines less effective
- tricyclic antidepressants (doxepin)
- opioid receptor effectors
- NSAIDs may have a role
- biologic agents or methotrexate for severe refractory pruritus[23]
- case report of 10-year history of chronic, severe recalcitrant pruritus due to primary sclerosing cholangitis with symptomatic resolution in 16 months with medical marijuana[21]
- systemic glucocorticoids for severe, intractable itching
- neuropathic pruritus
- gabapentin
- carbamazepine
- topical capsaisin
- pruritus due to myeloproliferative disorders may respond to SSRIs, but not antihistamines or NSAIDs
- mirtazapine may be useful for nocturnal pruritus, or pruritus due to renal disease, liver disease or lymphoma
- naltrexone or butorphanol may useful for pruritus due to
- phototherapy for pruritus due to uremia, psoriasis or liver disease not responding to topical glucocorticoids[2]
- screening for cancer as indicated
More general terms
More specific terms
- anal pruritus
- aquagenic pruritus
- inguinal pruritus
- neurogenic pruritus
- neuropathic pruritus
- pruritoceptive pruritus
- psychogenic pruritus
- vulvar pruritus
Additional terms
References
- ↑ Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 908
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, 16, 17, 18. American College of Physicians, Philadelphia 1998, 2006, 2009, 2012, 2015, 2018
- ↑ Takahashi S, In: Intensive Course in Geriatric Medicine & Board Review, Marina Del Ray, CA, Sept 29-Oct 2, 2004
- ↑ 4.0 4.1 van Laarhoven AIM et al Role of induced negative and positive emotions in sensitivity to itch and pain in women. Br J Dermatol 2012 Aug; 167:262 PMID: https://www.ncbi.nlm.nih.gov/pubmed/22404598
- ↑ 5.0 5.1 Mishra SK, Hoon MA. The cells and circuitry for itch responses in mice. Science 2013 May 24; 340:968 PMID: https://www.ncbi.nlm.nih.gov/pubmed/23704570
- ↑ 6.0 6.1 Siegel FP et al. Aquagenic pruritus in polycythemia vera: Characteristics and influence on quality of life in 441 patients. Am J Hematol 2013 Aug; 88:665 PMID: https://www.ncbi.nlm.nih.gov/pubmed/23657863
- ↑ Greaves MW. Recent advances in pathophysiology and current management of itch. Ann Acad Med Singapore. 2007 Sep;36(9):788-92. PMID: https://www.ncbi.nlm.nih.gov/pubmed/17925991
- ↑ O'Donoghue M, Tharp MD. Antihistamines and their role as antipruritics. Dermatol Ther. 2005 Jul-Aug;18(4):333-40. PMID: https://www.ncbi.nlm.nih.gov/pubmed/16297006
- ↑ 9.0 9.1 Zirwas MJ, Seraly MP Pruritus of unknown origin: a retrospective study. J Am Acad Dermatol. 2001 Dec;45(6):892-6. PMID: https://www.ncbi.nlm.nih.gov/pubmed/11712035
- ↑ Berger TG, Shive M, Harper GM. Pruritus in the older patient: a clinical review. JAMA. 2013;310(22):24432450 PMID: https://www.ncbi.nlm.nih.gov/pubmed/24327039
- ↑ 11.0 11.1 Fett N, Haynes K, Propert KJ, Margolis DJ. Five-year malignancy incidence in patients with chronic pruritus: a population-based cohort study aimed at limiting unnecessary screening practices. J Am Acad Dermatol. 2014 Apr;70(4):651-8. PMID: https://www.ncbi.nlm.nih.gov/pubmed/24485529
- ↑ Cassano N, Tessari G, Vena GA, Girolomoni G Chronic pruritus in the absence of specific skin disease: an update on pathophysiology, diagnosis, and therapy. Am J Clin Dermatol. 2010 Dec 1;11(6):399-411 PMID: https://www.ncbi.nlm.nih.gov/pubmed/20866115
- ↑ Reamy BV, Bunt CW, Fletcher S. A diagnostic approach to pruritus. Am Fam Physician. 2011 Jul 15;84(2):195-202. PMID: https://www.ncbi.nlm.nih.gov/pubmed/21766769
- ↑ Stander S, Weisshaar E, Mettang T et al Clinical classification of itch: a position paper of the International Forum for the Study of Itch. Acta Derm Venereol. 2007;87(4):291-4. PMID: https://www.ncbi.nlm.nih.gov/pubmed/17598029
- ↑ Yosipovitch G, Bernhard JD Clinical practice. Chronic pruritus. N Engl J Med. 2013 Apr 25;368(17):1625-34 PMID: https://www.ncbi.nlm.nih.gov/pubmed/23614588
- ↑ Patel T, Yosipovitch G. The management of chronic pruritus in the elderly. Skin Therapy Lett. 2010 Sep;15(8):5-9. PMID: https://www.ncbi.nlm.nih.gov/pubmed/20844849
- ↑ Butler DF, James WD Medscape: Pruritus and Systemic Disease http://emedicine.medscape.com/article/1098029-overview
- ↑ 18.0 18.1 DermNet NZ. Itch, pruritus (images) http://www.dermnetnz.org/systemic/itch.html
- ↑ Lambert J. Pruritus in female patients. Biomed Res Int. 2014;2014:541867. Review. PMID: https://www.ncbi.nlm.nih.gov/pubmed/24711996 Free PMC Article
- ↑ Silverberg JI. Practice Gaps in Pruritus. Dermatol Clin. 2016 Jul;34(3):257-61. Review. PMID: https://www.ncbi.nlm.nih.gov/pubmed/27363881 Free PMC Article
- ↑ 21.0 21.1 Roh YS, Sutaria N, Biles NF et al Treatment of Chronic Pruritus With Medical Marijuana. JAMA Dermatol. Published online April 9, 2021 PMID: https://www.ncbi.nlm.nih.gov/pubmed/33835147 https://jamanetwork.com/journals/jamadermatology/fullarticle/2778442
- ↑ 22.0 22.1 Deng J et al. Risk of hematologic cancer in patient with undifferentiated pruritis. JAMA Dermatol 2022 Jul; 158:791. PMID: https://www.ncbi.nlm.nih.gov/pubmed/35612839 PMCID: PMC9134041 (available on 2023-05-25) https://jamanetwork.com/journals/jamadermatology/fullarticle/2792454
- ↑ 23.0 23.1 23.2 Kilgore C Chronic Itch in Older Adults: Workup and Management Advice. Medscape. August 07, 2024 https://www.medscape.com/viewarticle/chronic-itch-older-adults-workup-and-management-advice-2024a1000eih
- ↑ 24.0 24.1 24.2 Roh YS, Choi J, Sutaria N, Kwatra SG. Itch: Epidemiology, clinical presentation, and diagnostic workup. J Am Acad Dermatol. 2022 Jan;86(1):1-14. PMID: https://www.ncbi.nlm.nih.gov/pubmed/34428534 PMCID: PMC8678917 Free PMC article. Review.
- ↑ 25.0 25.1 Manjunath J, Liao V, Kambala A et al Immune stimulus exposure as a trigger for the development of chronic pruritus and circulating blood type 2 inflammation. JAAD Int. 2024 Apr 7;16:97-102. PMID: https://www.ncbi.nlm.nih.gov/pubmed/38868400 PMCID: PMC11166869 Free PMC article.