These Eosinophilic Fasciitis statistics were compiled from the online postings by selected EF patients from 2010 through 2020. The selected patients all had a clinical diagnosis of Eosinophilic Fasciitis (EF). The online forums are English speaking so most of the patients posting online live in North America. A patient’s PRESENTATION given in Geneva, Switzerland, in June 2017 explains how the statistics were compiled. Some facts compiled from the online postings of EF patients are in the FINDINGS document.
CHARTS:
01 – Count online patients by COUNTRY (pdf)
02 – Count online patients by AGE in decades when symptoms appeared (pdf)
03 – Count online patients by YEARS to reach their last known state (pdf)
04 – Count online patients who took each DRUG (pdf)
05 – Compare TIME TO DIAGNOSIS with time to reach remission (pdf)
06 – Count online patients who took each TREATMENT and group them by their progress (pdf)
07 – Compare the TREATMENTS that online patients credit the most (pdf)
08 – Count the TRIGGERS that online patients suspect the most (txt)
09 – Count the SYMPTOMS that online patients mention the most (txt)
10 – Count the THERAPIES that online patients mention the most (txt)
Demographics
Online postings by EF patients show no clear demographics for this disease other than more females than males which is typical for autoimmune diseases in general. If we look again at patient AGES the pattern is similar to what the clinical studies have found. The proportion of females in their fifties is even higher in the online forums than in the studies. This might be a forum effect or it might be related to that time in female life. Child patients seem to be mostly female. Unlike American studies, a Japanese study found a male predominance: Characteristics of Japanese patients with eosinophilic fasciitis
Prevalence of EF in the USA
The world-wide prevalence of Eosinophilic Fasciitis (EF) is not known. A French study using the capture-recapture method gave an estimate of 14 cases of EF per million in Alsace, France. That estimate may be too low because some EF patients are mis-diagnosed and other EF patients recover without treatment or knowing what they had. It is possible to make a plausible guess at its prevalence in the U.S. by comparing it to the figures for a related disorder – Eosinophilic Esophagitis (EoE). Estimates for the prevalence of EoE range from 10 to 100 per 100,000 in the general population:
2009 – “55.0 per 100,000 persons” – PMC3026355
2013 – “56.7/100,000 persons” – www.cghjournal.org
2017 – “between 10 and 57 cases/100,000 persons” – pubmed
2017 – “40 in 100,000” – PMC5479411
2018 – “30–52 cases per 100,000 inhabitants” – PMC6192373
2018 – “as high as 55 per 100 000 population” – www.cmaj.ca
2018 – “0.5 to 1 case per 1000” (50 to 100 per 100,000) – www.sciencedirect.com
Those reports observe that the incidence of EoE is increasing which suggests that the prevalence of EoE is likely to be in the upper range of the quoted figures, therefore an estimate of 70 per 100,000 seems reasonable. The comparative figure for EF can be guessed as follows. First we can compare the two main Facebook groups for these diseases, both groups having a similar demographic. In 2020 the Facebook group for EoE had 13000 members with an average increase of around 1000 new members per year. The Facebook group for EF had 390 members averaging around 65 new members per year. This suggested there were roughly 15 EoE patients for one EF patient. Next we compared searches for “eosinophilic” as counted by www.wordtracker.com which gave an almost identical result, there were 15 searches for “eosinophilic esophagitis” for each search for “eosinophilic fasciitis”. That the two figures (15) matched seemed significant. Taking the presumed EoE prevalence of 70/100,000 gave a corresponding figure of around 5/100,000 for EF. In the U.S. population of 330 million this would mean around 230,000 people with EoE and around 16,000 people with EF which is 1 in 20 thousand. While EF is very rare, this does show that often quoted estimate of “only a few hundred cases” is far below the probable number. It seems likely that most cases of EF go undiagnosed or are mistaken for something else. While these estimates lack the scientific rigour of capture-recapture methods, they can give us a rough guide until better statistics are available.
[updated: 2025-07-06]