EGPA is the most rare of the three anti-neutrophil cytoplasmic antibody-associated vasculitides, with an estimated annual incidence of between 1 and 3 cases per million people.[6]Watts RA, Carruthers DM, Scott DG. Epidemiology of systemic vasculitis: changing incidence or definition? Semin Arthritis Rheum. 1995 Aug;25(1):28-34.
http://www.ncbi.nlm.nih.gov/pubmed/8525388?tool=bestpractice.com
[7]Watts RA, Lane SE, Bentham G, et al. Epidemiology of systemic vasculitis: a ten-year study in the United Kingdom. Arthritis Rheum. 2000 Feb;43(2):414-9.
http://www.ncbi.nlm.nih.gov/pubmed/10693883?tool=bestpractice.com
[8]Gonzalez-Gay MA, Garcia-Porrua C, Guerrero J, et al. The epidemiology of the primary systemic vasculitides in northwest Spain: implications of the Chapel Hill Consensus Conference definitions. Arthritis Rheum. 2003 Jun 15;49(3):388-93.
http://onlinelibrary.wiley.com/doi/10.1002/art.11115/full
http://www.ncbi.nlm.nih.gov/pubmed/12794795?tool=bestpractice.com
[9]Reinhold-Keller E, Herlyn K, Wagner-Bastmeyer R, et al. Stable incidence of primary systemic vasculitides over five years: results from the German vasculitis register. Arthritis Rheum. 2005 Feb 15;53(1):93-9.
http://onlinelibrary.wiley.com/doi/10.1002/art.20928/full
http://www.ncbi.nlm.nih.gov/pubmed/15696553?tool=bestpractice.com
[10]Ntatsaki E, Carruthers D, Chakravarty K, et al; BSR and BHPR Standards, Guidelines and Audit Working Group. BSR and BHPR guideline for the management of adults with ANCA-associated vasculitis. Rheumatology (Oxford). 2014 Dec;53(12):2306-9.
http://rheumatology.oxfordjournals.org/content/53/12/2306.long
http://www.ncbi.nlm.nih.gov/pubmed/24729399?tool=bestpractice.com
Among asthma patients, the incidence is as high as 67 per million asthma patients.[11]Loughlin JE, Cole JA, Rothman KJ, et al. Prevalence of serious eosinophilia and incidence of Churg-Strauss syndrome in a cohort of asthma patients. Ann Allergy Asthma Immunol. 2002 Mar;88(3):319-25.
http://www.ncbi.nlm.nih.gov/pubmed/11926627?tool=bestpractice.com
[12]Harrold LR, Andrade SE, Go AS, et al. Incidence of Churg-Strauss syndrome in asthma drug users: a population-based perspective. J Rheumatol. 2005 Jun;32(6):1076-80.
http://www.ncbi.nlm.nih.gov/pubmed/15940771?tool=bestpractice.com
EGPA is typically diagnosed in middle age, and there is a slight male predominance.[4]Keogh KA, Specks U. Churg-Strauss syndrome: clinical presentation, antineutrophil cytoplasmic antibodies, and leukotriene receptor antagonists. Am J Med. 2003 Sep;115(4):284-90.
http://www.ncbi.nlm.nih.gov/pubmed/12967693?tool=bestpractice.com
[5]Solans R, Bosch JA, Perez-Bocanegra C, et al. Churg-Strauss syndrome: outcome and long-term follow-up of 32 patients. Rheumatology (Oxford). 2001 Jul;40(7):763-71.
http://rheumatology.oxfordjournals.org/cgi/reprint/40/7/763.pdf
http://www.ncbi.nlm.nih.gov/pubmed/11477281?tool=bestpractice.com
[13]Guillevin L, Cohen P, Gayraud M, et al. Churg-Strauss syndrome: clinical study and long-term follow-up of 96 patients. Medicine (Baltimore). 1999 Jan;78(1):26-37.
http://www.ncbi.nlm.nih.gov/pubmed/9990352?tool=bestpractice.com
The outcome in EGPA is dependent on the extent and severity of organ involvement. In most cases, with appropriate immunosuppressive therapy, survival seems comparable to age-matched controls, with published 5-year survival rates of 68% to 100%.[14]Mukhtyar C, Flossmann O, Hellmich B, et al; European Vasculitis Study Group (EUVAS). Outcomes from studies of antineutrophil cytoplasm antibody associated vasculitis: a systematic review by the European League Against Rheumatism systemic vasculitis task force. Ann Rheum Dis. 2008 Jul;67(7):1004-10.
http://ard.bmj.com/content/67/7/1004.long
http://www.ncbi.nlm.nih.gov/pubmed/17911225?tool=bestpractice.com
[15]Phillip R, Luqmani R. Mortality in systemic vasculitis: a systematic review. Clin Exp Rheumatol. 2008 Sep-Oct;26(5 suppl 51):S94-104.
http://www.ncbi.nlm.nih.gov/pubmed/19026150?tool=bestpractice.com
[16]Comarmond C, Pagnoux C, Khellaf M, et al; French Vasculitis Study Group. Eosinophilic granulomatosis with polyangiitis (Churg-Strauss): clinical characteristics and long-term followup of the 383 patients enrolled in the French Vasculitis Study Group cohort. Arthritis Rheum. 2013 Jan;65(1):270-81.
http://onlinelibrary.wiley.com/doi/10.1002/art.37721/full
http://www.ncbi.nlm.nih.gov/pubmed/23044708?tool=bestpractice.com
[17]Samson M, Puéchal X, Devilliers H, et al; French Vasculitis Study Group. Long-term outcomes of 118 patients with eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome) enrolled in two prospective trials. J Autoimmun. 2013 Jun;43:60-9.
http://www.ncbi.nlm.nih.gov/pubmed/23590801?tool=bestpractice.com
Myocardial and central nervous system involvement may confer greatest risk.